Crowbar

The Crowbar is a melee weapon. It is a unique weapon which deals critical hits right after destroying a door.

Location
The blueprint for the Crowbar is located in a secret area behind a special lore room where a scientist's corpse with a headcrab resides, along with that of the HEV Outfit. The room will always spawn unless both are collected and turned in to the collector.

Trivia

 * Along with the HEV Outfit, the Crowbar is a reference to the Half-Life series as the iconic melee weapon used by the protagonist Gordon Freeman.
 * This item, along with the Emergency Door, the HEV Outfit, and the "Half-Life" diet, were added alongside 6 new enemies in update v1.8.