"This year I decided to go as something really scary ... half-naked," DeGeneres joked during her Halloween opening monologue, airing today (Oct. 31). "Of course, I'm Nicki Minaj. Nicki was on the show a few weeks ago and her shirt was not ... she took our show from PG to double D, that's what she did!"
DeGeneres continued to poke fun at her costume, nicknaming her breasts her "boom booms" and her behind her "super bass" before showing off her best twerk.
See photos of Ellen vs. Nicki below and watch the hilarious video above: