The tentacle first appeared in Valve's Half-Life, released in 1998, as a towering creature in the Blast Pit section of the Black Mesa facility. Players had to move quietly past it, since it reacted to noise rather than sight, which made its growls and thrashing a memorable part of that level. The sound later spread through gameplay videos, horror edits and fan soundboards, where it became shorthand for an unseen creature lurking nearby. It remains popular because it is instantly recognisable to Half-Life fans and works even without any footage from the game.