This Ed Wood film of a killer targeting porn stars due to his forbidden lust for them and the demonization of the porn industry would make for a good riffing. My issues with the MST3K version is that some of the jokes of the porn stars come across as transphobic. I also would imagine jokes to be made of internet fetish porn. Specifically the talk of "new stuff" for the existing audience would be ripe for these types of jokes. As well as joking about how porn is made now versus how it was portrayed in the film would be rife for jokes as well.