Being killed (or owned) in any multiplayer video game with a considerably weak character. Derived from the Super Smash Bros. Melee character, Princess Peach, who is considered a weak character to play as.
May also apply to real life, depending on the nerdiness of the user.
Player 1, playing as Falco, is defeated -4 to +4, by Player 2, playing as Peach. Player 2 would then proceed to say "You got PEACH'D!"