The HECU, or Hazardous Environment Combat Unit, is the fictional military force sent to the Black Mesa Research Facility in Valve's Half-Life, first released in 1998. Its soldiers are known for short, barked radio commands that players hear throughout the game's combat sections, and those lines have long been reused in fan edits and soundboards. Short refusals like this one survive because they are instantly recognisable to Half-Life players, easy to drop into a reaction, and still carry the game's tense, military atmosphere more than twenty years later.