That's
this thing's scientific name. YIKES!
I did not trust the Wikipedia article (vampire squid from Hell? Light-emitting organs? Defensive cloud of glowing particles? Come on!) but then I came across this fascinating, creepy as fuck
National Geographic video showing Cthulu in its natural habitat, complete with helpful CGI animations.
Watching that video, I suddenly understood what H. P. Lovecraft must have felt like all the time.