we don't have to use trivialization or rape in this fic, but it has to evoke bad mental images for the agents involved.

that being said, what about everything else?

Goes without saying, I suppose, that what you're going for is a parody fic that'll make the reader laugh.

A reader who's totally grossed out or traumatized--in real life, not in the pretend way you might be if you were writing an MST--won't be having fun. Which means, if you were to include trivialized rape, etc., you'd go against the point of writing a parody.

Trivializing rape and abuse is not-funny and I don't think it could really be made funny. There are some exceptions, technically: black humor (ex., M.A.S.H), ridiculing a scary and horrible thing by using humor (ex., The Producers), or in a context that's long-established as making fun of everything, appropriate or not (ex., South Park). All of those contexts acknowledge the horribleness of the subject matter to some extent.

What I think would be funniest, would be to write the parody in such a way that the reader can laugh at its badness--to evoke ridiculous mental images, to make the reader realize that absolutely impossible things are happening in the story. Bad spelling and grammar should be used for a reason--not just to make it look badly written, but to "accidentally" create images that'll make the reader spit their coffee onto their keyboard.

IMO, one allowance can be made for trivialized murder: If writing an over-the-top Battle!Sue, having them kill off an army of "bad guys", while implying that the author has absolutely no idea what that might involve and is just trying to make the Sue look insanely badass because s/he is better than any fighter EVAR, could probably be played for humor. But... it'd have to be done right to avoid looking like trivialized genocide, which is probably not to be touched unless you are also a good enough writer to make Hitler look deservedly ridiculous.