Azathoth
From Multiversal Omnipedia
Azathoth is the idiot god, the Daemon Sultan, the Primal Chaos. It sits in the center of Ultimate Chaos, blaspheming eternally, being accompanied by fellow Outer Gods while they madly pipe flutes. Azathoth is sometimes said to be responsible for the creation of the universe, and may destroy it in the end- it is the most powerful Outer God.
According to some, Azathoth was stripped of its sanity after being defeated by the [Elder Gods]- according to others, it was always mad.