A person who has diluted themselves into believing that their ideas, created in and voiced solely from their ass, are pure genius.
Woman: So you're trying to tell me the inflatable party sheep was just a gag gift, and it came with the KY smears and pubic hair already stuck to it?
Man: Yes! It's really quite remarkable, isn't it?
Woman: Stop talking out of your ass!
Man: Oh, come on - that story was brilliant! It's like I'm an Ass Genius or something!