An exclamation used during the time of the Black Plague in order to let people know that the cart for dead bodies was passing by. Anyone who had a friend or housemate that had recently died of the plague would literally "bring out their dead" and throw the person on top of the pile.

A classic scene from "Monty Python and the Holy Grail" where a man tries to put his living grandpa on the cart of dead bodies.

After pwnage, this phrase is one that may be uttered, to avoid clichés such as all your base and pwn3d