If you really want to freak your cat, give him a bath. I do not recommend the method in the following absolutely true story. (Have I ever lied to you?)

There's this really intelligent guy who was one of my wife's co-workers. He had several university degrees, and worked for a US government think tank. Smart. Well, . . . not entirely smart. One day he decided to give his cat a bath. The easy way was to get in the shower with the cat, lather it up and rinse it off quickly, then set it out on the bathmat to dry. Simple, except the cat didn't see it that way. Just as the shower door clicked shut, the cat figured out what was going on and went into buzz saw mode. It took the paniced cat ten or fifteen seconds to find the opening above the shower door. That is a long, long time to be in a small slippery place with a tree-climbing, fire-spitting, squalling, blood-letting buzz saw. The cat was disgruntled and a little wet, but the man . . . . well, let's just say he was wiser, and didn't quite bleed to death.
Just for the record, cats are self-cleaning pets.
Do not try this at home.
Howard