Warning: Contains spoilers for Doom Patrol season 3 episode 9.
In Doom Patrol season 3, The Brotherhood of Evil are revealed to have planned to steal Niles Caulder’s creations from the future so that the Brain could steal Niles’ legacy and beat him at the invention game. However, the events of Doom Patrol season 3 demonstrate that the Brain is already as good or better at inventing things than Niles was himself. This requires some time travel magic and it is unclear if the Brain realizes what he has done.
The Brain has held a vendetta against Niles Caulder and was always mad that Niles’ Doom Patrol kept the Brain’s team, the Brotherhood of Evil, at bay. The source of their rivalry has not been fully explained in the Doom Patrol show; however, in the Doom Patrol comics, the Brain was a scientist that Niles actually blew up in the hopes of using his brain to create the first Robotman. In Doom Patrol, the Brain wishes to steal the Robotman body that Niles has created and is frustrated that he was never able to build one for himself - a borderline impossible task, as Niles had used a combination of both science and magic to create the body.
While Niles was able to create Robotman’s body to 1917 with Rita Farr (April Bowlby), allowing the Brain to see the machine and then “invent” it in the first place. The time machine then sits in storage until 1949 when Rita takes it back to 2021 (pausing to ensure her own death along the way). Unfortunately, the Brain likely does not realize that he was the true originator of the time machine as he has never talked to Rita and therefore does not know that the one that he copied was the same one that he built.
The rules of time travel for the Doom Patrol continuity are established in season 3, and while this time machine invention doesn’t technically break those rules, it does create a time loop that doesn’t really make sense. When Laura De Mille finds the movie that she created with the Sisterhood of Dada, she notices that Rita Farr is visible in the film. This happens before Rita has traveled back in time, meaning that any time travel that is going to happen has technically already happened and cannot change the future. This is why the time machine can already exist in the past before the Brain has had the idea to create it: because all of those events have already taken place. However, the timeline still relies on the Brain discovering how to build a time machine by seeing the time machine that he already built, which is obviously absurd.
However, while this time machine time loop is ridiculous, it is entirely in keeping with Doom Patrol’s usual choices that lead to an absurdist style where the Sisterhood of Dada can feel right at home. The surrounding absurdist themes imply that this time loop ridiculousness is not a mistake or a classic failure of time travel storytelling, but rather an intentional stylistic choice made by Doom Patrol writers to lean into that absurdity. The intentionality of the choice is emphasized when a potential plot hole comes up with how the Brain knew to send Garguax to Codsville seventy years before Rita would be there and the issue is dismissed by lampshading it with him saying “Don’t ask me how I figured all that out.”
Doom Patrol releases new episodes Thursdays on HBO Max.