Shoggoth

Shoggoth are beings made of sentient, self-shaping flesh. In most cases, these beings appear as a formless mass of flesh, tentacles and bug-like eyes. It is difficult to kill them due to the fact that looking at a Shoggoth's form induces feelings of horror in humans and drives them insane.

Trivia

 * "Shoggoth" are originally beings from H.P. Lovecraft's Cthulhu Mythos lore.