From the game, Bioshock. Basically he's a behemoth mofo that is damn near impossible to bring down only with weapons. Usually near the demented children in the underwater city, Big Daddy will stop at nothing to protect that little girl.
Player 2: OMFG GTFO! theres a Big Daddy ready to pounce on your ass and beat you down like a schoolgirl!
Player 1: heh, bacon