(Planet of the Apes) The Planet of the Apes is actually a post-apocalyptic Earth. They put this Statue of Liberty shot on the actual Blu-Ray cover. It was also parodied on Family Guy.
(Metroid) Samus Aran, underneath the power suit, is a woman. The instruction manual refers to Samus as male to obscure her gender until the surprise reveal at the end of the game, but nowadays, Zero Suit Samus is a playable character in most Smash titles.
(Dr. Jekyll and Mr. Hyde) The two characters are actually split personalities of the same person. In the book, this is a massive revelation, but the title of the book is now synonymous for someone with a secret dark side.
No offense but do you have the slightest bit how little that narrows it down? They’ve parodied just about everything. Also they were FARRR from the first to do so in this case