At least most of him/her stays dry. I've thought about getting a nanny cam to see what my cat gets up to when I'm gone, but have decided it's best I don't know.
My mother had to bathe her kitten twice after he jumped in the toilet before it was flushed.
He is no longer allowed in the bathroom when it is occupied. We are also forced to keep the TP on an overhead shelf after he discovered how much fun it was to unwind an entire roll off the holder and then shred it.
Bathrooms - like Disneyworld for cats.