Team Fortress 2 is Valve's class based shooter released in 2007, where the Spy relies on a cloaking watch and disguises to infiltrate the enemy team. The uncloak sound became a key audio cue in matches, warning nearby players that an invisible opponent had materialised close by. Clips and edits later carried the effect beyond the game into meme videos and soundboards, where its short shimmer alone is enough for fans to picture a Spy appearing behind an unsuspecting victim.