The Killer Robot was one of the many monsters captured by the Facility and was used to kill people to appease the Elder Gods. It is presumed that it was summoned when somebody tampered with a dog whistle-like object. The Killer Robot was one of the first monsters to be released during the Purge and quickly grabbed two guards with its grappling hook hands and killed them with its buzz-saw appendages. It was later seen chasing to workers down a flight of stairs, wildly swinging its buzz-saws about. It was more than likely killed when the Elder Ones awoke.