Doug Rattmann,[2][3] also known as the Ratman,[5] is a former Aperture Science employee, and one of the few survivors of GLaDOS' flooding of the Enrichment Center with neurotoxin. Introduced through his murals in Portal, his story was expanded in Portal 2: Lab Rat. When working for Aperture Science, Rattmann was charged with the maintenance of the Aperture Image Format, an interactive graphics format created in 1985. He had access to Aperture Science's bulletin board system, with the login…