Now, I'm fairly sure this hasn't been done before, but I'd appreciate it if you told me if it has.
So, the idea is an anomalous being that can rewrite any document, video, or other form of media it knows about and has seen, and rewrite the memories of those involved in creating the piece of media, those who were involved in the piece of media, and those who have seen the piece of media.
It's an interesting idea, but I'm kind of stuck on where to go with it. It could be humanoid, but then I run into the problem of X-men syndrome. It could be a monster - which could lead to some interesting possibilities, considering the containment procedures would likely involve amnestics, and the amount of non-humanoid pages I've seen where part of the containment procedures require that they be given amnestics are zero - but the "seems friendly but turns out to be murderous" thing has already been done before. Sure, it's done by rewriting memory rather then just acting, but the point still stands. So, if you guys could help me out, that would be great.