Oh hai.
Eko Eko Azarak! Eko Eko Zomelak! Sumo! Atho Femalak!
—Cthulhu's signature chant
Cthulhu is a mysterious creature created by Bob Saget with the sole purpose of wreaking havoc upon mankind. For thousands of years Saget commanded Cthulhu to sleep for almost an eternity in the sunken city of R'yleh, since Cthulhu needs a lot of beauty sleep to get to his full power. Right now, Bob Saget is awaiting the time for Cthulhu to arise and destroy mankind. Cthulhu is a light sleeper, however, and regularly gets up to go and destroy a mortal civilization of some sort.
There is currently no known way to prevent Cthulhu's wrath once he has decided on a target. Theorists suggest that saying "please" may have an effect, but tests are inconclusive as the feces of the researchers have not been recovered. Eternal Sailor Moon and her Team were able to escape Cthulhu, though it's likely that he'll try to battle them once he finally awakens.