Back in 1988 I went to see this movie in the theaters with some friends (girls), and when I left, I had almost no feeling in my arms from being squeezed and clawed. There's nothing like seeing scary movies with girls, by the way.

The Serpent and the Rainbow (1988)

Bill Pullman stars as an anthropologist sent to Haiti to discover the truth behind stories of zombies. A pharmaceutical company wants the formula for raising the dead so they can make a ton of money. Zombies are the new cash-crop, I guess. Poor old Bill gets in a little deeper than he originally bargained for, and gets a spike in the sack. I defy you to not cross your legs or wince when it happens. Oh yeah, they make zombies and kill people a lot, too. Great movie.