The crowbar is seen in the campaign mission "The Corridor of Death". Cole uses it to break boards off of blocked doorways and to break into a German ammo storage room. The Crowbar has no lethal capabilities, however it is still usable.
The crowbar is a melee weapon that appears in the zombies map Attack of the Radioactive Thing. It is found inside a small room in the motel, behind Bombstoppers. In order to acquire it, the player must simply interact with it. The crowbar replaces the player's standard melee and it is an one-hit-kill weapon until round 8. The crowbar is required in order to acquire the Alien Fuses or complete the map's main easter egg.