This is what happens when you write a movie in a room full of idiots.
Crossovers can be good.
When Darby O'Gill teamed up with the Little People it was magic. Tarzan vs. Predator is way better than just Tarzan. And besides the time where Fonzie jumped the Grand Caynon, the best episode of Happy Days was when Mork visited from space and hit the Fonz with the freeze ray. The title sounds like someone was trying to write a movie with refrigerator poetry and there were no good words left. And, of course, they're retarded.