Roundhog

A character or creature in a shooter video game which does not carry a weapon and thus, when killed, does not drop any rounds of ammunition to be picked up and used by the player. When faced with multiple roundhogs the player slowly runs out of ammunition and is forced to use melee attacks.

Player 1: Why are you only using your crowbar on those zombies?
Player 2: Because I have no ammo left, these things are just roundhogs!