Crowbar

"I cannot WAIT to find a crate!"

- Nick

"Any crates around here?"

- Coach

The Crowbar is a close-combat weapon introduced in Left 4 Dead 2.

The Crowbar (or any melee weapon for that matter) is not to be used against Boomers or Spitters, for obvious reasons. It would take time to get to a Charger, Jockey, Hunter or Smoker, but would not be as dangerous to the player to do so.