I had an idea for a universal ride:

Doc Brown makes a submarine time machine so he can study the evolution of marine animals making their first migrations to land. While booting up the subolorean, it is attacked by Jaws and they both get transported through the warp field to a prehistoric era. To prevent the future from being erased, Doc Brown and the riders have to save Jaws from being killed by all the other giant ancient marine animals, while at the same time trying to keep jaws from eating the evolutionary precursor to modern man.