Doug Rattmann



Doug Rattmann, commonly nicknamed as the Rat Man, was a scientist at the Aperture Science Enrichment Center. Prior to the events of Portal while GLaDOS began flooding the entire facility with neurotoxin, Rattmann is the only known employee to have survived. A paranoid, he is dependent on anti-psychotic medication as a means of keeping him sane.

Rattmann does not appear in-game in any form, instead leaving behind paintings and murals which can be found throughout the backstage of various testing chambers in Portal and the single-player campaign of Portal 2.

Portal 2: Lab Rat


In the Portal 2: Lab Rat comic, he is revealed to be an Aperture Science employee who worked on the Handheld Portal Device.

Portal


Delusional, running low on medication and travelling with what he sees to be a talking Weighted Companion Cube, he watches from the shadows as Chell is put through GLaDOS' testing course. Although he is never spotted in-game in any of the playable Portal series, his refuge areas (referred to as dens) can be found by Chell, containing crude bedding, empty cans of beans and scribblings and dioramas on the walls. It is in one of these dens that the warning phrase "The cake is a lie" can be found scribbled on a wall; as GLaDOS continually promises that there would be cake at the end of testing.

Portal 2
During the events of the single-player campaign of Portal 2, Rattmann's fate is left unknown. Whether or not he is dead is left up to debate, as Chell's cryogenic stasis bed that she used before the events of Portal he took refuge in, had disappeared entirely. One piece of evidence for his death is the song called "Ghost of Rattmann". Some speculate that Rattmann may have made it to the moon, as shown in a hidden picture encrypted into the game's audio file. You can find the audio file by bringing a radio into Rattmann's den in Portal 2 Chapter 2 Test Chamber 6.



All that is left of him in Portal 2, like in the first game, are wall scribblings and various dioramas depicting either what he witnessed or simply what he feels like expressing.

Rattmann's graffiti work makes no appearances whatsoever during the game's Cooperative Testing Initiative.

Known dens
Aside from leaving paintings, murals and messages behind, Doug Rattmann also discovered a number of hidden rooms in Aperture Science. He adorned these rooms with messages and artwork and primarily used them as refuges in order to escape GLaDOS' scrutiny. The hidden rooms are present in both Portal and Portal 2, and are known as the Ratman's Dens. A total of 13 have been discovered, 6 in Portal and 7 in Portal 2.

Trivia

 * Doug Rattmann was behind the Aperture Image Format, used in the Portal ARG.
 * Doug Rattmann's [[Media:Doug_Rattmann_Sp_a2_pull_the_rug_r2.ogg|voice]] can be heard in certain Rat-Man dens in Portal 2, and during the Portal 2 OST track "Ghost of Rattman". These are both voiced by former Valve writer Marc Laidlaw.
 * The “Armstrong Cube” artwork references his transmission in Portal 2 Chapter 2 Test Chamber 6. If one follows the actions to achieve Final Transmission, the radio emits a Morse-code like sound. When translated, the noise leads to a staticky image of a Weighted Companion Cube on the lunar surface.
 * Various wall art by Rattmann can be found in the Portal 2 Adventure World in Lego Dimensions, along with a hidden Den. The infamous "cake is a lie" scribblings can also be found on walls, though instead of trailing off, it ends with "the cake is in the kitchen on the second floor."
 * Over a year later, the game's developers teased that there were still undiscovered secrets within Lego Dimensions, one of which was related to Portal. In November of 2016, players finally discovered that Doug Rattmann himself was hidden throughout various parts of the level "GLaD to Meet You".