Hey, this thread exists! Cool!
Wanted to float a couple of ideas here:
I'd love a house themed to the original Transformers cartoon. On that show, the Autobots live on this big spaceship called the Ark, and there are numerous Decepticon characters in that mythology that turn into robot beasts or grotesque creatures, like the Terrorcons and Sharkticons, so I feel like the thing to do would be to have a house where the Ark is overrun by these characters, so you have a total Autobot slaughter while the core cast of Optimus, Bumblebee, Ironhide, Ratchet, Jazz, etc. try to find them off. The money shot show scene here would probably be the Terrorcons, who can combine, forming Abominus, their merged form. Bonus points if the queue video here is a new episode or two of the cartoon that lays down the backstory.
The other idea I had, that I'm fairly surprised never happened, was a house based on the Thriller video; I genuinely think you could do something cool if you do as the video did, where it starts in the movie and goes out into the street/cemetery. Would the zombies here be dancing? I dunno if I'd wanna put that on the scareactors, but I'd certainly have them appear in the house.