I have just suddenly realized that Jared Padalecki is most likely a shape shifter. Evidence is limited to includes how in The Benders he suddenly looks like he could be Maggie Mackenzie's Kathleen's twin brother, especially at the end when they're looking at each other and he just nods and walks away and lets her shoot Pa Bender. My mind may be a little warped by how ridiculously hot he is in that scene when he's kicking ass and breathing hard, but we'll ignore that little bit of data because it is, obviously, completely irrelevant.
Jared Padalecki is an empathic shape shifter. Whenever he has a moment with someone, his face subtly shifts to show that not only does he feel their emotions, he even becomes them just a little bit. Alien? Angel? Demigod? The evidence is not yet conclusive, but the truth is out there.
This is Kathleen
This is Sam
They may in fact be the same person! Only time, and further research, will tell.