| This minifigure has only appeared in video game(s)|
Although this article is about an official minifigure, it never existed in physical form, or appeared in any official LEGO sets.
Information from the Half-Life Wiki
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 "drattmann" and the password "h0nee". He apparently never directly took part in GLaDOS' construction.
Rattmann and Henry chat while the latter is working on GLaDOS. At some point late in GLaDOS' construction, Doug went to see his colleague Henry while he was working on the AI in his chamber. Henry praised their technological advances, stating that artificial consciousness is the next frontier. Doug was not convinced by this since GLaDOS attempted to kill everyone each time she was turned on, forcing them to switch her off. Later, Doug came across Henry while he was designing the Morality Core. Henry asked him to turn it on, then Doug asked him what it was, to which Henry answered that it was the latest in AI inhibition technology, that it would act on GLaDOS as her conscience. Rattmann believed it was insufficient to stop her murderous intentions, arguing that "you can always ignore your conscience."
Rattmann jumps into the file room. When GLaDOS was activated in 200-, she became self-aware, locked down the facility, and flooded the Enrichment Center with deadly neurotoxins. Rattmann was one of the only survivors, and GLaDOS turned onto taunting him about his schizophrenia. She attempted to convince him that his situation was a result of his paranoia, but he ignored her.
Rattmann got a hunch about a Test Subject, Chell, who he thought could make a difference. He fled to the file room and found her file. It said that she should not be tested, as she is abnormally stubborn and "Never gives up. Ever." Convinced she is the one he needs to stop GLaDOS, he put her on top of the Test Subject list, so that she would be the first to be picked in the next test.
Rattmann then spent the next several months surviving in the Test Chambers and maintenance areas of Aperture. Having only two anti-psychotic pills left, he kept them for the day GLaDOS would wake Chell. Consequently, he slowly lost his sanity, his schizophrenia completely taking him over.
He spent hours scribbling on walls, painting murals, graffiti and arrows and hints for the day Chell would wake up and try to escape, and became obsessed with the Companion Cube that his schizophrenia made talk to him and give him advice, acting as his source of logic. It also appears he had several Cubes, as his scribblings show him mourning over the loss of one.
His scribbles and artwork on the walls could be a temporary fix to his illness. This can be inferred from Rattmann reading a book called, "Art Therapy" in the comic Portal 2: Lab Rat.
- He has been hiding in the game for over a year, since it came out, and was just discovered November 2016.
- You can find one of his dens in the game with some of his murals on the wall.