Canon vs. Fanon, part 22: Goa'uld fanon
Welcome to the latest canon vs. fanon! Poke around, find holes in my reasoning, or just sit back and enjoy. :)
The purpose of these essays is to explore canon issues, contrast them with common fanon usage, and determine how far fanon strays from canon. Canon is defined as anything directly shown during Stargate: The Movie, episodes of the show, and the SG-1 movies; show supersedes the original movie when there's a contradiction. (The Jaffa do not have phlanged voices; Goa'uld are snakelike, not white Asgard with sharp teeth.) Fanon is defined as widely-accepted concepts that appear in fanfic, but do not have any real basis in canon.
There are varying degrees of fanon, and these essays have touched on all types. Some fanon is completely unsupported by canon; some is actually contradicted by canon; and some is only a question of emphasis or degree. The point is not to condemn authors who use fanon, or even to suggest that there is something wrong with extrapolation of common plotlines. I am not a canon purist, even though I usually prefer it! The purpose is simply to reach an understanding of what is and isn't canon. Once the facts and conclusions are presented, you are welcome to argue them, agree them, or ignore them completely -- the choice is entirely up to you. :) I conclude each essay with my personal opinion, which is not canonical at all.
If you're new to the Canon vs. Fanon series, you can read older entries via the tags or the index. Please be aware that now that SG-1 is closed canon, I am no longer warning for spoilers.
The topic of this section will be Goa'uld fanon. If I’ve missed something, whether it confirms or contradicts my analyses, please comment and let me know -- especially if it involves S9-10 canon, with which I'm less familiar! And please remember that I'm not deliberately trying to mock any specific writer, or even whole groups of writers; I'm only pointing out what's fanon, and what's actually canon.
For similar topics, you might enjoy perusing the discussions on Daniel pleading for the life of the host, Goa'uld and sarcophagus use, and the use of MRIs to detect Goa'uld.
The System Lords lust after SG-1 as potential hosts.
This fanon trope isn't a Goa'uld leaping from a dead host or canopic jar into the nearest body, which just happens to be Sam or Jack or Daniel; rather, the idea is that Apophis or one of the other System Lords wants to replace its own host with a member of SG-1. This makes for lovely drama, usually in the shape of an elaborate trap designed to get the intended host alone and helpless. The rest of SG-1 desperately races the clock to find their missing teammate in time to rescue him or her before implantation takes place and a close friend becomes a deadly enemy.
While these kind of stories are often fun, how grounded is such Goa'uld behavior in actual canon?
First of all, it's important to recognize that it's very, very rare for a Goa'uld to actually change hosts. Certainly, there need to be mitigating circumstances other than, "Daniel Jackson is young and attractive" or "Samantha Carter's blue eyes and blond hair will make for a most fetching host." (Yes, I have seen those reasons cited in fanfic. No, I can't point you to these stories, as I certainly didn't keep the links.) Other, more pragmatic motives have been suggested: Sam's skills, Daniel's multiple languages, Jack's military knowledge. But here are a few canon factoids to consider:
Hathor/Cure. Hathor tells Daniel that she needs human DNA to ensure that her babies will be implant successfully; on Pangara, Teal'c says, "Prior to the process of incubating Goa'uld symbiotes using Jaffa, the blending between Goa'uld and host had only a one in two chance of success. The Jaffa were created for the very reason of improving the ability of the symbiote to take human hosts... To the best of my knowledge, a failed blending results in death to both Goa'uld and host." While Teal'c's knowledge may not be entirely complete, his statement, taken together with Hathor's, does suggest that implanation isn't entirely risk-free. For older and more powerful symbiotes, that might be a risk they aren't willing to take.
The Devil You Know/The Serpent's Venom/Enemies. After Apophis has been resurrected and tortured repeatedly by Sokar, his face is scarred enough that he has some kind of metal prosthesis/bandage on his face. By the time we meet him again a year later, he is back in power; yet the metal piece is still there, which suggests that it can't be healed by the sarcophagus that we know he has. Yet despite being one of the most powerful System Lords by the end of Season Four, it apparently has not occurred to him to switch to a non-damaged host.
Rite of Passage. Nirrti is the Goa'uld that seems to be most open to switching hosts, as she actively works to create a hok'taur with the intention of claiming the advanced human for herself. (More on this later.) Yet despite being a prisoner of the System Lords after her attempted assassination of Cronus, she doesn't seem to find it worthwhile to switch hosts to a less hunted face when she escapes.
Homecoming. Oshu, Yu's First Prime, explains to Teal'c that his master spends all his time in the sarcophagus, as his host is failing:
Teal'c asks, "Why does he not take another host?"
Oshu replies, "I believe he has reached the point where he is incapable. Lord Yu is the oldest of the System Lords."
Now, Oshu is Jaffa, and hardly privy to Goa'uld secrets. His theory might be wrong. But if he's right, then Yu clung to his host even as the body aged beyond repair, rather than switch to another.
We know symbiotes will seek a host; we have the evidence of Kawalsky, of Pangara, even the naquadah-less symbiotes of The First Ones. We see minor Goa'uld switching hosts when their current host dies, as the symbiote inside the Unas did in Demons (and Jolinar leapt into Sam). Even System Lords will do so if it's absolutely necessary, as Osiris did when it implanted Sarah Gardener when she released it from captivity. But System Lords seem to prefer to keep their hosts as long as the body is still healthy and viable.
How often do we actually see an intention to switch hosts in canon?
COTG. While it is never specified that Amaunet has been in other hosts before, a cursory look at Egyptian mythology suggests that she's much too powerful to be a freshly-matured symbiote. It seems logical to assume that Amaunet's former host died and she is shacking out in a priestess' symbiote pouch until Apophis finds her a new host that's to her liking.
Secrets. Sha're tells Teal'c and Daniel that Apophis intends her unborn child to be his new host. There is no mention yet of harcesis, although Sha're might not know about that aspect. We do know that both Amaunet and Apophis actively pursued knowledge of Shifu, but whether Sha're's assumption of Apophis' intentions were correct is somewhat unclear. If she was right, this is a clear example of a Goa'uld wanting to abandon its host for a more powerful one.
Serpent's Song. Apophis is dying from being tortured by Sokar and begs for a host, since his current one is beyond the help of anything beyond a sarcophagus.
Singularity/Rite of Passage/Metamorphosis. Nirrti is obsessed with the idea of creating a more advanced human to serve as her host, thus lending her more power.
Dominion. Ba'al captures Adria and takes her as his host so that he can have access to the Orici's powers.
That gives us five incidents over ten years, although only two of them actually occur: one due to the loss of a former host, and one due to a more advanced host. In all five cases, the motive is either survival or power, not a preference for blue eyes or knowledge of the SGC.
So, how many times does a member of SG-1 face personal implantation?
In the Line of Duty. Sam gets snaked by Jolinar, but it's not because she's a member of SG-1; it's because she's there.
Serpent's Song. Included for the sake of completion. When Sam tries to question Apophis, he senses the marker left by Jolinar and recognizes that she's carried a symbiote before. He suggests that Sokar might be interested in implanting her with Sokar's queen. This seems to be more of a psychological threat than anything else, though.
Into the Fire. This one qualifies as a technicality. Hathor has Jack implanted, but not for herself; instead, she has him snaked in order to become a useful minion.
Singularity/Rite of Passage/Metamorphosis. Nirrti idly threatens Sam with implantation: "Major Carter. I am pleased to have such an excellent subject. I might even consider you for my new host." But it's clear that Nirrti isn't interested in Sam so much as DNA-improved!Sam, as she insists on putting Sam into the DNA machine and awaiting any further results.
Nightwalkers. Sam is temporarily implanted by a cloned symbiote for the specific purpose of infiltrating the SGC.
If you look at that list, it seems a bit ironic that the closest thing to the fanon trope of a Goa'uld wanting a member of SG-1 for personal and/or strategic reasons occurs during a situation caused by the rogue NID. But it's pretty clear that the Goa'uld are interested in either survival or enhanced power, not strategic knowledge or SG-1's fetching good looks. The one exception is Hathor, whose entire purpose in Out of Mind/Into the Fire is acquiring information; and she only considers implantation when the much more elaborate "you've been frozen for decades, let's have a clip show" plot fails. Even then, Hathor expresses no interest in taking over one of the team, but rather plans to have them snaked by a subordinate.
ETA2: aurora_novarum points out that in Full Alert, the Trust has been infiltrated by Goa'uld who are deliberately trying to provoke war between Russia and the U.S., presumably in order to get their hands on the Ancient outpost in Antarctica. Sam theorizes that the Goa'uld got hold of the NID when they were scouting out which planets to destroy with symbiote poison, although that's never confirmed. But this is definitely a case of Goa'uld choosing hosts for strategic purposes, rather than for power. Influenced by the attitudes of their hosts, perhaps? It's difficult to say. Again, it must be pointed out that these are minor Goa'uld, not major players -- the System Lords clearly have little or no interest in switching hosts if they can help it.
Conclusion: Goa'uld only switch hosts when their current body is failing or the new host is more advanced and powerful. There is no canon to support the casual switching of hosts to claim a member of SG-1.
The Goa'uld cause physical pain to their hosts in order to subdue them and/or torment them with memories of past atrocities.
It makes sense, doesn't it? If the symbiote can control a body and heal it, it can also cause pain. It certainly makes for excellent drama, as friends are forced to watch the suffering host writhe in agony without being able to help. Interestingly, however, this is based on a canon threat, not canon incidents:
Into the Fire. Hathor threatens Daniel, Sam, and Jack in turn with implantation. Sam says defiantly, "I'm not afraid!"
"You should be, my dear," Hathor purrs, "for the pain a symbiote can inflict on its host is unimaginable."
Now, there's no reason to actually suspect that Hathor is lying. But there's also no reason to suspect that this is true, either.
(I have this vague idea that there was another Goa'uld who threatened a potential host with great pain, but I was unable to find such a reference. If someone could point me in the right direction, I would greatly appreciate it.)
It's interesting to note that when hosts speak of their suffering at the hands of their symbiotes, it is always in reference to emotional distress at what they were forced to do:
Thor's Hammer. Daniel anxiously asks Kendra if the Hammer was painful. Kendra answers, "It was nothing compared to the suffering I watched myself inflict on others for all those years." She later describes the Hammer as "needles stabbing inside the head" and attributes it to the symbiote's desire to remain in control, but that is pain inflicted by the Hammer, not be the Goa'uld. This suggests that Kendra sees herself as deserving pain and punishment for what she did when she was a host, but then, poor Kendra was definitely suffering from PTSD.
Pretense. Skaara address the Triad: "What I suffer each day is worse than death... I remember the demon stretching out my hand to kill Danyer, the husband of my sister. There was nothing I could do to stop it. And I have seen many more, far worse atrocities than this."
It should also be noted that there is no canon suggestion that the host is tormented by memories of past atrocities committed before the blending. We do know that the host can perceive what is happening around them; there is the testimony of Kendra and Skaara cited above, and Sha're's recognition of Teal'c in Secretsas "the shol'va," based on Apophis' ranting in Amaunet's presence. But there is nothing to indicate that former hosts have any memories of the symbiote's actions in previous hosts, whether it's a deliberate trauma inflicted by the Goa'uld or accidental absorption via the blending of minds.
ETA1: campylobacter points out that there actually are canon references to former hosts retaining memories and/or emotions: Sam and Jolinar. To be fair, this might be because Jolinar, as a Tok'ra, was more willing to share with Sam. But she certainly had flashes to Jolinar-in-Rosha in her dreams, and she felt a familiarity and closeness with Martouf. This is only vague stuff, though, and she needs the memory device in Jolinar's Memories to really access anything properly. There's also Vala in Memento Mori, who is mind-probed by Athena in an effort to ferret out the code to an Ancient tablet that Qetesh obtained when Vala was her host. This isn't a past memory, though; much like Sha're in Secrets, it's Vala retaining some memory of her time as Qetesh, despite being suppressed. So while it may be wrong to assert that there is no accidental absorption via the blending of minds, it's certainly true that outside of the Tok'ra, any such retention of memory is restricted to the host's experiences with the symbiote and is often below the level of conscious retrieval.
ETA3: thothmes adds another Tok'ra data point: Saroosh talking to Jacob about blending with Selmac.
"You will probably be overwhelmed by the knowledge and wisdom you will gain upon blending... I won't deceive you, sir. We have some pretty awful things buried in our memory... Memories of countless Goa'uld atrocities, the loss of the host before me. And you will feel the mourning for my loss."
This is Saroosh talking about what Jacob will remember and know while he is still blended with Selmac, and again, it's a Tok'ra, who is more likely to be willing to share. This might simply be a case of not having sufficient data to decide with regards to the Goa'uld. It's clear the Tok'ra allow the hosts to absorb memories and emotions of previous events, but with no evidence of anything similar from the Goa'uld, I do believe the conclusion is still a solid one.
ETA4: And one more data point, courtesy of ivorygates: poor Anna in Resurrection, who has all of Sekmet's memories when her personality shifts. But since Anna is a cloned symbiote/human hybrid, her memories are actually the symbiote's. It's interesting that she remembers nothing at all when the harcesis switch is toggled, isn't it?
Conclusion: While the hosts are forced to bear witness to what the Goa'uld do in their own bodies, there is no real canon evidence that they suffer physically or have any knowledge of actions or events that the symbiote caused in previous hosts.
Before Qetesh was removed from Vala, the Tok'ra tortured her for information from the symbiote.
Vala's backstory is somewhat difficult to determine, as it's never entirely clear when she's embellishing the truth. :) Let's start with what she tells Daniel in Prometheus Unbound:
After she uses a healing device on Daniel's shoulder, Daniel accuses her of being a Goa'uld. "No," Vala contradicts, "but I was once host to one." She later elaborates, "Ten years ago, a Tok'ra incited a rebellion on my planet... The Goa'uld was captured alive, tortured, and beaten for days on end. I was host to that Goa'uld at the time. The people didn’t understand that it was the symbiote that had ruled over them so harshly. I guess the Tok'ra felt responsible. He rescued me, removed the Goa'uld symbiote, and nursed me back to health."
In The Powers That Be, Vala repeats this: "A Tok'ra eventually removed the symbiote but not before her people rebelled and tortured me, thinking we were one and the same." As this essentially matches her original version and she actually plans an effort against the Ori incursion based on her subsequent pretense of still being Qetesh, it seems likely that this is true.
Regarding her experiences after she was freed of Qetesh, she spins an elaborate sob story in Ties That Bind: "I was taken as a host. And even though the Tok'ra eventually freed me, the damage was already done. And once you have been spat on and stoned by the people of your own village..."
Daniel at first sympathizes, then turns suspicious: "Sometimes I just forget that you've been through -- if you've actually been through any of that. Are you messing with me?"
Vala gives an unrepentant grin and asks, "Is it working?" and Daniel throws her out of the room.
Is Vala's account actually true? It's impossible to know. There are only two canon references to her life post-Qetesh and pre-Prometheus Unbound:
The Powers That Be. Vala admits that she enslaved the people on P8X-412 for four years after Qetesh was removed by posing as the Goa'uld.
Family Ties. Vala somehow managed to retrieve the box where she kept the trinkets her father gave her in her childhood.
There is nothing there to suggest that before the Tok'ra removed Qetesh, they tortured Qetesh-in-Vala -- meaning, essentially, that they tortured Vala -- to get as much information as possible from the symbiote. In fact, there's a hint of canon that actually contradicts it:
Dominion. When the Tok'ra show up to remove Ba'al from Adria and replace him with a Tok'ra symbiote, Vala exchanges a somewhat tense nod with the Tok'ra, but does not display the kind of animosity or revulsion that we might expect if she'd truly suffered at Tok'ra hands. She does not protest to their presence nor try to avoid them, although she does retreat from the actual operation when Ba'al is removed. Nothing in her behavior indicates a previous bad encounter.
Since there's no canon to suggest Vala's torture and her reactions in Dominion make it appear somewhat unlikely, why is the idea that the Tok'ra tortured Vala to get information out of Qetesh so accepted in the fandom? The answer is simple: Salieri wrote a short fic in December 2005 entitled Speaking of Vala which is so powerful, so horribly plausible, that it entered fandom consciousness as fact. I will discuss my own fascination with this in the personal fanon section, but for now:
Conclusion: There is no canon evidence that the Tok'ra tortured Vala for information from Qetesh before removing the symbiote.
My personal fanon opinion? I can buy the wanting SG-1 as host thing under certain circumstances: Osiris or Anubis, for example, being interested in Daniel post-Ascension, or Ba'al considering the advantages of Jack as host if he discovers Jack's Ancient gene. But it seems to me that it would be much more likely for a System Lord to enjoy watching a member of SG-1 be implanted by a lesser Goa'uld, someone who would be subservient. That would be more satisfying, after all.
There's also another point to consider: strategic thinking. As in, most Goa'uld don't have any. :) Certainly it would make sense to us that a Goa'uld would want to implant someone from the SGC in order to gain immediate access to GDO codes, the layout of the base, the Tau'ri way of thinking, etc. But to most Goa'uld, human thinking and skills are beneath contempt, the province of slaves. I imagine that for most of the System Lords, the idea that the Tau'ri are something more than worms to be crushed underfoot would be simply unthinkable. Daniel's grasp of languages? A Goa'uld would simply decree that everyone should speak his language. Sam's knowledge of technology? How can puny Earth possess knowledge that is worthy of consideration? Jack's military skills or Mitchell's pilot ability? Completely beneath a Goa'uld's interest. There are minons for that kind of thing!
The one exception to all this is Ba'al, who seems to be the one System Lord capable of escaping entrenched thinking. While I despise Ba'al's storyline in most of S9-10, in earlier seasons he is shown as pragmatic, shrewd, and capable of thinking outside the box. And, of course, his actions in Dominion and Continuum were superbly Ba'al-like, although still with that element of Goa'uld narcissism that led to his downfall. But even then, Ba'al pursued power -- Adria's abilities, ascendancy over the other System Lords. So even for him, I find the idea of his jumping hosts to someone from SG-1 to be highly unlikely.
Then there's the concept of torturing the host, either physically or emotionally. Both ideas certainly are Goa'uld-like. If a Goa'uld can heal its host and extend the lifespan, it should be equally capable of, say, tweaking nerves to feel phantom pain, or interfering temporarily with crucial body functions. And sadism, too, fits the Goa'uld mold nicely, making it easy to suppose that a symbiote would enjoy tormenting its host with memories of past atrocities it committed in previous hosts. But neither one has any basis in canon.
The closest we get to physical torture of the host is Klorel telling Apophis that he needs more time in the sarcophagus to keep Skaara under control, and there has never been any suggestion that sarc time is torture (on the contrary, in fact, even if the events before the sarcophagus usually involve pain.) That doesn't mean that it's not an interesting and useful bit of fanon that can be employed at a writer's discretion.
I do think that emotional distress induced by past memories doesn't quite fit Goa'uld behavior, though. Consider that genetic memory is a double-edged sword: it gives the Goa'uld tremendous resources and abilities, but it also causes them to be, well, Goa'uld. This is why Shifu, as harcesis, is a forbidden creation and is hotly pursued by both Apophis and Amaunet. To me, it seems that the Goa'uld would percieve those memories as a weapon, a thing of power. Why show those memories to the hosts and thereby give them even a little bit of an edge? For that reason, I would buy the fanon of physical torture of the host, but not the emotional one of memories of past atrocities. Deliberately committing atrocities that a helpless host must watch is, of course, par for the course for the Goa'uld. I do think Klorel chose to ribbon Daniel not just because he was able to grab him, but because he was Skaara's good brother.
Finally, there is the fascinating (to me) bit of fanon regarding Vala's experiences with the Tok'ra. I say it's fascinating, because this is precisely the kind of fanon that I love. That might seem like a shocking statement on the surface for someone who has written 22 essays on canon vs. fanon. :) But I have never suggested that the fandom should stick to precisely what's on the screen. My own preference is for canon compliance -- that is, extrapolation and expansion from the canon without contradicting canon characterization or events. And Salieri's fabulous story fits that so perfectly. It fits cool Tok'ra pragmatism that all too often sets lesser importance on the host, and it adds layers of depth and nuance to Vala. Is it fanon? Yes. Should writers be, at the very least, aware that it's fanon? Certainly. But that doesn't mean it shouldn't be used, because for all my love of canon and proper characterization, I have even more love for the glorious osmosis of fandom that can take canon and shape it to become something that is so much more!
"Anyway, I'm sorry, but that just happens to be how I feel about it. What do you think?"
The purpose of these essays is to explore canon issues, contrast them with common fanon usage, and determine how far fanon strays from canon. Canon is defined as anything directly shown during Stargate: The Movie, episodes of the show, and the SG-1 movies; show supersedes the original movie when there's a contradiction. (The Jaffa do not have phlanged voices; Goa'uld are snakelike, not white Asgard with sharp teeth.) Fanon is defined as widely-accepted concepts that appear in fanfic, but do not have any real basis in canon.
There are varying degrees of fanon, and these essays have touched on all types. Some fanon is completely unsupported by canon; some is actually contradicted by canon; and some is only a question of emphasis or degree. The point is not to condemn authors who use fanon, or even to suggest that there is something wrong with extrapolation of common plotlines. I am not a canon purist, even though I usually prefer it! The purpose is simply to reach an understanding of what is and isn't canon. Once the facts and conclusions are presented, you are welcome to argue them, agree them, or ignore them completely -- the choice is entirely up to you. :) I conclude each essay with my personal opinion, which is not canonical at all.
If you're new to the Canon vs. Fanon series, you can read older entries via the tags or the index. Please be aware that now that SG-1 is closed canon, I am no longer warning for spoilers.
The topic of this section will be Goa'uld fanon. If I’ve missed something, whether it confirms or contradicts my analyses, please comment and let me know -- especially if it involves S9-10 canon, with which I'm less familiar! And please remember that I'm not deliberately trying to mock any specific writer, or even whole groups of writers; I'm only pointing out what's fanon, and what's actually canon.
For similar topics, you might enjoy perusing the discussions on Daniel pleading for the life of the host, Goa'uld and sarcophagus use, and the use of MRIs to detect Goa'uld.
The System Lords lust after SG-1 as potential hosts.
This fanon trope isn't a Goa'uld leaping from a dead host or canopic jar into the nearest body, which just happens to be Sam or Jack or Daniel; rather, the idea is that Apophis or one of the other System Lords wants to replace its own host with a member of SG-1. This makes for lovely drama, usually in the shape of an elaborate trap designed to get the intended host alone and helpless. The rest of SG-1 desperately races the clock to find their missing teammate in time to rescue him or her before implantation takes place and a close friend becomes a deadly enemy.
While these kind of stories are often fun, how grounded is such Goa'uld behavior in actual canon?
First of all, it's important to recognize that it's very, very rare for a Goa'uld to actually change hosts. Certainly, there need to be mitigating circumstances other than, "Daniel Jackson is young and attractive" or "Samantha Carter's blue eyes and blond hair will make for a most fetching host." (Yes, I have seen those reasons cited in fanfic. No, I can't point you to these stories, as I certainly didn't keep the links.) Other, more pragmatic motives have been suggested: Sam's skills, Daniel's multiple languages, Jack's military knowledge. But here are a few canon factoids to consider:
Hathor/Cure. Hathor tells Daniel that she needs human DNA to ensure that her babies will be implant successfully; on Pangara, Teal'c says, "Prior to the process of incubating Goa'uld symbiotes using Jaffa, the blending between Goa'uld and host had only a one in two chance of success. The Jaffa were created for the very reason of improving the ability of the symbiote to take human hosts... To the best of my knowledge, a failed blending results in death to both Goa'uld and host." While Teal'c's knowledge may not be entirely complete, his statement, taken together with Hathor's, does suggest that implanation isn't entirely risk-free. For older and more powerful symbiotes, that might be a risk they aren't willing to take.
The Devil You Know/The Serpent's Venom/Enemies. After Apophis has been resurrected and tortured repeatedly by Sokar, his face is scarred enough that he has some kind of metal prosthesis/bandage on his face. By the time we meet him again a year later, he is back in power; yet the metal piece is still there, which suggests that it can't be healed by the sarcophagus that we know he has. Yet despite being one of the most powerful System Lords by the end of Season Four, it apparently has not occurred to him to switch to a non-damaged host.
Rite of Passage. Nirrti is the Goa'uld that seems to be most open to switching hosts, as she actively works to create a hok'taur with the intention of claiming the advanced human for herself. (More on this later.) Yet despite being a prisoner of the System Lords after her attempted assassination of Cronus, she doesn't seem to find it worthwhile to switch hosts to a less hunted face when she escapes.
Homecoming. Oshu, Yu's First Prime, explains to Teal'c that his master spends all his time in the sarcophagus, as his host is failing:
Teal'c asks, "Why does he not take another host?"
Oshu replies, "I believe he has reached the point where he is incapable. Lord Yu is the oldest of the System Lords."
Now, Oshu is Jaffa, and hardly privy to Goa'uld secrets. His theory might be wrong. But if he's right, then Yu clung to his host even as the body aged beyond repair, rather than switch to another.
We know symbiotes will seek a host; we have the evidence of Kawalsky, of Pangara, even the naquadah-less symbiotes of The First Ones. We see minor Goa'uld switching hosts when their current host dies, as the symbiote inside the Unas did in Demons (and Jolinar leapt into Sam). Even System Lords will do so if it's absolutely necessary, as Osiris did when it implanted Sarah Gardener when she released it from captivity. But System Lords seem to prefer to keep their hosts as long as the body is still healthy and viable.
How often do we actually see an intention to switch hosts in canon?
COTG. While it is never specified that Amaunet has been in other hosts before, a cursory look at Egyptian mythology suggests that she's much too powerful to be a freshly-matured symbiote. It seems logical to assume that Amaunet's former host died and she is shacking out in a priestess' symbiote pouch until Apophis finds her a new host that's to her liking.
Secrets. Sha're tells Teal'c and Daniel that Apophis intends her unborn child to be his new host. There is no mention yet of harcesis, although Sha're might not know about that aspect. We do know that both Amaunet and Apophis actively pursued knowledge of Shifu, but whether Sha're's assumption of Apophis' intentions were correct is somewhat unclear. If she was right, this is a clear example of a Goa'uld wanting to abandon its host for a more powerful one.
Serpent's Song. Apophis is dying from being tortured by Sokar and begs for a host, since his current one is beyond the help of anything beyond a sarcophagus.
Singularity/Rite of Passage/Metamorphosis. Nirrti is obsessed with the idea of creating a more advanced human to serve as her host, thus lending her more power.
Dominion. Ba'al captures Adria and takes her as his host so that he can have access to the Orici's powers.
That gives us five incidents over ten years, although only two of them actually occur: one due to the loss of a former host, and one due to a more advanced host. In all five cases, the motive is either survival or power, not a preference for blue eyes or knowledge of the SGC.
So, how many times does a member of SG-1 face personal implantation?
In the Line of Duty. Sam gets snaked by Jolinar, but it's not because she's a member of SG-1; it's because she's there.
Serpent's Song. Included for the sake of completion. When Sam tries to question Apophis, he senses the marker left by Jolinar and recognizes that she's carried a symbiote before. He suggests that Sokar might be interested in implanting her with Sokar's queen. This seems to be more of a psychological threat than anything else, though.
Into the Fire. This one qualifies as a technicality. Hathor has Jack implanted, but not for herself; instead, she has him snaked in order to become a useful minion.
Singularity/Rite of Passage/Metamorphosis. Nirrti idly threatens Sam with implantation: "Major Carter. I am pleased to have such an excellent subject. I might even consider you for my new host." But it's clear that Nirrti isn't interested in Sam so much as DNA-improved!Sam, as she insists on putting Sam into the DNA machine and awaiting any further results.
Nightwalkers. Sam is temporarily implanted by a cloned symbiote for the specific purpose of infiltrating the SGC.
If you look at that list, it seems a bit ironic that the closest thing to the fanon trope of a Goa'uld wanting a member of SG-1 for personal and/or strategic reasons occurs during a situation caused by the rogue NID. But it's pretty clear that the Goa'uld are interested in either survival or enhanced power, not strategic knowledge or SG-1's fetching good looks. The one exception is Hathor, whose entire purpose in Out of Mind/Into the Fire is acquiring information; and she only considers implantation when the much more elaborate "you've been frozen for decades, let's have a clip show" plot fails. Even then, Hathor expresses no interest in taking over one of the team, but rather plans to have them snaked by a subordinate.
ETA2: aurora_novarum points out that in Full Alert, the Trust has been infiltrated by Goa'uld who are deliberately trying to provoke war between Russia and the U.S., presumably in order to get their hands on the Ancient outpost in Antarctica. Sam theorizes that the Goa'uld got hold of the NID when they were scouting out which planets to destroy with symbiote poison, although that's never confirmed. But this is definitely a case of Goa'uld choosing hosts for strategic purposes, rather than for power. Influenced by the attitudes of their hosts, perhaps? It's difficult to say. Again, it must be pointed out that these are minor Goa'uld, not major players -- the System Lords clearly have little or no interest in switching hosts if they can help it.
Conclusion: Goa'uld only switch hosts when their current body is failing or the new host is more advanced and powerful. There is no canon to support the casual switching of hosts to claim a member of SG-1.
The Goa'uld cause physical pain to their hosts in order to subdue them and/or torment them with memories of past atrocities.
It makes sense, doesn't it? If the symbiote can control a body and heal it, it can also cause pain. It certainly makes for excellent drama, as friends are forced to watch the suffering host writhe in agony without being able to help. Interestingly, however, this is based on a canon threat, not canon incidents:
Into the Fire. Hathor threatens Daniel, Sam, and Jack in turn with implantation. Sam says defiantly, "I'm not afraid!"
"You should be, my dear," Hathor purrs, "for the pain a symbiote can inflict on its host is unimaginable."
Now, there's no reason to actually suspect that Hathor is lying. But there's also no reason to suspect that this is true, either.
(I have this vague idea that there was another Goa'uld who threatened a potential host with great pain, but I was unable to find such a reference. If someone could point me in the right direction, I would greatly appreciate it.)
It's interesting to note that when hosts speak of their suffering at the hands of their symbiotes, it is always in reference to emotional distress at what they were forced to do:
Thor's Hammer. Daniel anxiously asks Kendra if the Hammer was painful. Kendra answers, "It was nothing compared to the suffering I watched myself inflict on others for all those years." She later describes the Hammer as "needles stabbing inside the head" and attributes it to the symbiote's desire to remain in control, but that is pain inflicted by the Hammer, not be the Goa'uld. This suggests that Kendra sees herself as deserving pain and punishment for what she did when she was a host, but then, poor Kendra was definitely suffering from PTSD.
Pretense. Skaara address the Triad: "What I suffer each day is worse than death... I remember the demon stretching out my hand to kill Danyer, the husband of my sister. There was nothing I could do to stop it. And I have seen many more, far worse atrocities than this."
It should also be noted that there is no canon suggestion that the host is tormented by memories of past atrocities committed before the blending. We do know that the host can perceive what is happening around them; there is the testimony of Kendra and Skaara cited above, and Sha're's recognition of Teal'c in Secretsas "the shol'va," based on Apophis' ranting in Amaunet's presence. But there is nothing to indicate that former hosts have any memories of the symbiote's actions in previous hosts, whether it's a deliberate trauma inflicted by the Goa'uld or accidental absorption via the blending of minds.
ETA1: campylobacter points out that there actually are canon references to former hosts retaining memories and/or emotions: Sam and Jolinar. To be fair, this might be because Jolinar, as a Tok'ra, was more willing to share with Sam. But she certainly had flashes to Jolinar-in-Rosha in her dreams, and she felt a familiarity and closeness with Martouf. This is only vague stuff, though, and she needs the memory device in Jolinar's Memories to really access anything properly. There's also Vala in Memento Mori, who is mind-probed by Athena in an effort to ferret out the code to an Ancient tablet that Qetesh obtained when Vala was her host. This isn't a past memory, though; much like Sha're in Secrets, it's Vala retaining some memory of her time as Qetesh, despite being suppressed. So while it may be wrong to assert that there is no accidental absorption via the blending of minds, it's certainly true that outside of the Tok'ra, any such retention of memory is restricted to the host's experiences with the symbiote and is often below the level of conscious retrieval.
ETA3: thothmes adds another Tok'ra data point: Saroosh talking to Jacob about blending with Selmac.
"You will probably be overwhelmed by the knowledge and wisdom you will gain upon blending... I won't deceive you, sir. We have some pretty awful things buried in our memory... Memories of countless Goa'uld atrocities, the loss of the host before me. And you will feel the mourning for my loss."
This is Saroosh talking about what Jacob will remember and know while he is still blended with Selmac, and again, it's a Tok'ra, who is more likely to be willing to share. This might simply be a case of not having sufficient data to decide with regards to the Goa'uld. It's clear the Tok'ra allow the hosts to absorb memories and emotions of previous events, but with no evidence of anything similar from the Goa'uld, I do believe the conclusion is still a solid one.
ETA4: And one more data point, courtesy of ivorygates: poor Anna in Resurrection, who has all of Sekmet's memories when her personality shifts. But since Anna is a cloned symbiote/human hybrid, her memories are actually the symbiote's. It's interesting that she remembers nothing at all when the harcesis switch is toggled, isn't it?
Conclusion: While the hosts are forced to bear witness to what the Goa'uld do in their own bodies, there is no real canon evidence that they suffer physically or have any knowledge of actions or events that the symbiote caused in previous hosts.
Before Qetesh was removed from Vala, the Tok'ra tortured her for information from the symbiote.
Vala's backstory is somewhat difficult to determine, as it's never entirely clear when she's embellishing the truth. :) Let's start with what she tells Daniel in Prometheus Unbound:
After she uses a healing device on Daniel's shoulder, Daniel accuses her of being a Goa'uld. "No," Vala contradicts, "but I was once host to one." She later elaborates, "Ten years ago, a Tok'ra incited a rebellion on my planet... The Goa'uld was captured alive, tortured, and beaten for days on end. I was host to that Goa'uld at the time. The people didn’t understand that it was the symbiote that had ruled over them so harshly. I guess the Tok'ra felt responsible. He rescued me, removed the Goa'uld symbiote, and nursed me back to health."
In The Powers That Be, Vala repeats this: "A Tok'ra eventually removed the symbiote but not before her people rebelled and tortured me, thinking we were one and the same." As this essentially matches her original version and she actually plans an effort against the Ori incursion based on her subsequent pretense of still being Qetesh, it seems likely that this is true.
Regarding her experiences after she was freed of Qetesh, she spins an elaborate sob story in Ties That Bind: "I was taken as a host. And even though the Tok'ra eventually freed me, the damage was already done. And once you have been spat on and stoned by the people of your own village..."
Daniel at first sympathizes, then turns suspicious: "Sometimes I just forget that you've been through -- if you've actually been through any of that. Are you messing with me?"
Vala gives an unrepentant grin and asks, "Is it working?" and Daniel throws her out of the room.
Is Vala's account actually true? It's impossible to know. There are only two canon references to her life post-Qetesh and pre-Prometheus Unbound:
The Powers That Be. Vala admits that she enslaved the people on P8X-412 for four years after Qetesh was removed by posing as the Goa'uld.
Family Ties. Vala somehow managed to retrieve the box where she kept the trinkets her father gave her in her childhood.
There is nothing there to suggest that before the Tok'ra removed Qetesh, they tortured Qetesh-in-Vala -- meaning, essentially, that they tortured Vala -- to get as much information as possible from the symbiote. In fact, there's a hint of canon that actually contradicts it:
Dominion. When the Tok'ra show up to remove Ba'al from Adria and replace him with a Tok'ra symbiote, Vala exchanges a somewhat tense nod with the Tok'ra, but does not display the kind of animosity or revulsion that we might expect if she'd truly suffered at Tok'ra hands. She does not protest to their presence nor try to avoid them, although she does retreat from the actual operation when Ba'al is removed. Nothing in her behavior indicates a previous bad encounter.
Since there's no canon to suggest Vala's torture and her reactions in Dominion make it appear somewhat unlikely, why is the idea that the Tok'ra tortured Vala to get information out of Qetesh so accepted in the fandom? The answer is simple: Salieri wrote a short fic in December 2005 entitled Speaking of Vala which is so powerful, so horribly plausible, that it entered fandom consciousness as fact. I will discuss my own fascination with this in the personal fanon section, but for now:
Conclusion: There is no canon evidence that the Tok'ra tortured Vala for information from Qetesh before removing the symbiote.
My personal fanon opinion? I can buy the wanting SG-1 as host thing under certain circumstances: Osiris or Anubis, for example, being interested in Daniel post-Ascension, or Ba'al considering the advantages of Jack as host if he discovers Jack's Ancient gene. But it seems to me that it would be much more likely for a System Lord to enjoy watching a member of SG-1 be implanted by a lesser Goa'uld, someone who would be subservient. That would be more satisfying, after all.
There's also another point to consider: strategic thinking. As in, most Goa'uld don't have any. :) Certainly it would make sense to us that a Goa'uld would want to implant someone from the SGC in order to gain immediate access to GDO codes, the layout of the base, the Tau'ri way of thinking, etc. But to most Goa'uld, human thinking and skills are beneath contempt, the province of slaves. I imagine that for most of the System Lords, the idea that the Tau'ri are something more than worms to be crushed underfoot would be simply unthinkable. Daniel's grasp of languages? A Goa'uld would simply decree that everyone should speak his language. Sam's knowledge of technology? How can puny Earth possess knowledge that is worthy of consideration? Jack's military skills or Mitchell's pilot ability? Completely beneath a Goa'uld's interest. There are minons for that kind of thing!
The one exception to all this is Ba'al, who seems to be the one System Lord capable of escaping entrenched thinking. While I despise Ba'al's storyline in most of S9-10, in earlier seasons he is shown as pragmatic, shrewd, and capable of thinking outside the box. And, of course, his actions in Dominion and Continuum were superbly Ba'al-like, although still with that element of Goa'uld narcissism that led to his downfall. But even then, Ba'al pursued power -- Adria's abilities, ascendancy over the other System Lords. So even for him, I find the idea of his jumping hosts to someone from SG-1 to be highly unlikely.
Then there's the concept of torturing the host, either physically or emotionally. Both ideas certainly are Goa'uld-like. If a Goa'uld can heal its host and extend the lifespan, it should be equally capable of, say, tweaking nerves to feel phantom pain, or interfering temporarily with crucial body functions. And sadism, too, fits the Goa'uld mold nicely, making it easy to suppose that a symbiote would enjoy tormenting its host with memories of past atrocities it committed in previous hosts. But neither one has any basis in canon.
The closest we get to physical torture of the host is Klorel telling Apophis that he needs more time in the sarcophagus to keep Skaara under control, and there has never been any suggestion that sarc time is torture (on the contrary, in fact, even if the events before the sarcophagus usually involve pain.) That doesn't mean that it's not an interesting and useful bit of fanon that can be employed at a writer's discretion.
I do think that emotional distress induced by past memories doesn't quite fit Goa'uld behavior, though. Consider that genetic memory is a double-edged sword: it gives the Goa'uld tremendous resources and abilities, but it also causes them to be, well, Goa'uld. This is why Shifu, as harcesis, is a forbidden creation and is hotly pursued by both Apophis and Amaunet. To me, it seems that the Goa'uld would percieve those memories as a weapon, a thing of power. Why show those memories to the hosts and thereby give them even a little bit of an edge? For that reason, I would buy the fanon of physical torture of the host, but not the emotional one of memories of past atrocities. Deliberately committing atrocities that a helpless host must watch is, of course, par for the course for the Goa'uld. I do think Klorel chose to ribbon Daniel not just because he was able to grab him, but because he was Skaara's good brother.
Finally, there is the fascinating (to me) bit of fanon regarding Vala's experiences with the Tok'ra. I say it's fascinating, because this is precisely the kind of fanon that I love. That might seem like a shocking statement on the surface for someone who has written 22 essays on canon vs. fanon. :) But I have never suggested that the fandom should stick to precisely what's on the screen. My own preference is for canon compliance -- that is, extrapolation and expansion from the canon without contradicting canon characterization or events. And Salieri's fabulous story fits that so perfectly. It fits cool Tok'ra pragmatism that all too often sets lesser importance on the host, and it adds layers of depth and nuance to Vala. Is it fanon? Yes. Should writers be, at the very least, aware that it's fanon? Certainly. But that doesn't mean it shouldn't be used, because for all my love of canon and proper characterization, I have even more love for the glorious osmosis of fandom that can take canon and shape it to become something that is so much more!
"Anyway, I'm sorry, but that just happens to be how I feel about it. What do you think?"