Caribbean ride used real skeletons.
The engineers from Disney took one look at the fake skeletons that were initially brought in and thought that they weren’t creepy enough. This might be because prosthetics in the 1960s weren’t as convincing as they are now. To offer a more authentic experience, Disney engineers enlisted the help of the University of California Los Angeles’ anatomy department for real skeletons.
They replaced these real skeletons with fake ones, except one.