I read this a while, while back and I know it isn't actually a picture joke, so I rely on you to picture it:

A sadist, a masochist, a murderer, a necrophile, a zoophile and a pyromaniac are all sitting on a bench in a mental institution, bored out of their minds.

"How about having sex with a cat?" asked the zoophile.
"Let's have sex with the cat and then torture it," says the sadist.
"Let's have sex with the cat, torture it and then kill it," shouted the murderer.
"Let's have sex with the cat, torture it, kill it and then have sex with it again," said the necrophile.
"Let's have sex with the cat, torture it, kill it, have sex with it again and then burn it," said the pyromaniac.

Silence took over... and the masochist says:
"Meow."