Andy Warhol once had his portrait painted by oddball performance artist Neke Carson, who squatted in a kneeling position with his head between his legs and a pink felt-tip pen (with a special rubberized shaft) lodged firmly in his bottom.

Carson was widely praised for his so-called "rectal realist" style. "Boy," a Warhol associate remarked, "can that asshole paint!"

[Warhol documented the portrait session with a series of photographs.]