Shuma-Gorath

Shuma-Gorath is a fictional comic book character, a demon lord, who is part of the Marvel Universe. It first appeared in the pages of Marvel Premiere, and is better known for also being a playable character in the Marvel vs Capcom video games. It is likely that it was inspired by the Cthulhu Mythos.

Shuma-Gorath resembles a giant green eye with tentacles. Before the arrival of the First Host of the Celestials, Shuma-Gorath ruled the Earth and commanded human sacrifice, until the time-travelling sorceror Sise-Neg banished him. He managed to return and set himself up as a god during the Hyperborean Age, again commanding bloody sacrifice, but slaughtered those who sought his favour. Eventually, the power of Crom imprisoned him within a mountain. Even from that prison, he could interact with Conan the Barbarian, Kulan Gath, and many others, before Crom banished him back to his home dimension

When Shuma-Gorath tried to return to Earth through the mind of the Ancient One, he forced Dr. Strange to kill his master to prevent the powerful creature from arriving on Earth.

Years later, Strange was forced to destroy the talismans keeping the chaos demons at bay, to keep them from falling into the hands of an evil sorcerer. Strange was then forced to travel to Shuma-Gorath's dimension and fight it there to prevent the demons from invading Earth. To do so, Strange had to absorb the chaos magic into himself, gaining enough power to destroy Shuma-Gorath. However, he started to transform into a new Shuma-Gorath himself as a result, so he commited suicide to prevent that from happening. Fortunately, an ally of Strange was able to purify him on his way back to the living.

Shuma-Gorath was likely chosen for the Marvel vs. Capcom game because of its bizarre appearance. It is more likely that it will reappear on future versions of the game (if Capcom gets back the Marvel license, that is.), rather than in the comics.