The Sentry Turret debuted in Valve's Portal (2007), the first-person puzzle game set in the Aperture Science testing facility. Voiced by Ellen McLain, the same actress behind GLaDOS, the turrets greet the player with cheerful menace, and 'Searching...' is what they murmur when a target slips out of sight. The line became a favourite of Portal fans and quote compilations, and it now pops up in gaming memes, reaction edits and stream overlays whenever something or someone is hunting for an intruder.