A mimic monster may come to REPO in the future, but it has to be 'really interesting' before it does
In semiwork's recent Q&A, the question of whether or not mimics would ever come to REPO was answered, and you'll be pleased to know that it was a very firm "maybe." But since this isn't really a confirmation, nor is it a solid no, no details on how they'd work or what exactly this would mean in REPO were shared.
According to semiwork, there have been "talks about a mimic, actually from pretty early on in development, but if we want to add a mimic it needs to be really interesting." A few concept sketches of what a mimic could look like were also shared, taking the standard look of a semibot, or "Badbot" as they were labelled on the diagram, and making them look as if they were decomposing after taking on the form of a player. After this stage, it looks as if there were plans for the mimic to turn into a frenzied robot, flailing around and baring a mouth of fanged teeth. Similar to everyone's least favourite enemy, the Apex Predator.
I imagine this is just one idea of what a mimic could look like in the game, rather than it being the idea that semiwork is rolling with should this monster ever be unleashed. Especially since the team has been considering adding some form of mimic since REPO was in development.
As stated in the last Q&A video, there are plans for more monsters and possible variations to come later down the line, but it's too early to say what they will be and when they will appear. It's safe to assume that this is the same for the mimic too. Even though it likely won't be coming in the first significant update for the game, that's not to rule it out in the near future.
But while mimics aren't yet officially on the monster roster of REPO, semiwork also recognised that the demand probably stems from the number of mimic mods available for the game. We've touched on a few in our list of the best mods for REPO, such as the Mimic mod which gives monsters the opportunity to copy voice clips and repeat them back to the team, and the Wesley's Enemies mod which adds another robot into the game with the same appearance of a player. But seeing an actual mimic enemy in the game without the need for a mod would be a welcome addition.