GLaDOS is the sardonic artificial intelligence who oversees the test chambers in Valve's Portal games, and her calm, robotic announcements have become instantly recognisable to players. Short clips of her voice circulate widely on soundboards and in gaming videos, where they are reused as quick shorthand for a system warning, a target being acquired or a trap being sprung. Because the voice is so distinctive, even a one-second warning carries the atmosphere of Portal's sterile, watched facility, which is why editors keep reaching for it for reveals, ambushes and competitive moments.