GLaDOS is a fictional artificially superintelligent computer system from the video game series Portal. GLaDOS later appeared in The Lab and Lego Dimensions. The character was created by Erik Wolpaw and Kim Swift and voiced by Ellen McLain. GLaDOS is responsible for testing and maintenance in the Aperture Science Computer-Aided Enrichment Center in all titles. While GLaDOS initially appears in the first game to simply be a voice that guides the player, her words and actions become increasingly malicious as she makes her intentions clear. The second game, as well as the Valve-created comic Lab Rat, reveals that she was mistreated by the scientists and used a neurotoxin to kill the scientists in the laboratory before the events of Portal. She is apparently destroyed at the end of the first game but returns in the sequel, in which she is comically supplanted and temporarily stuck on a potato battery.