Zoophile, a Pyromaniac, a Murderer, a Necrophiliac and a Sadomasochist are all sitting together in the lounge area of a Mental Institute...
The Zoophile says, "I know, lets all shag the cat"
The Pyromaniac says, "Lets shag the cat, then set it on fire"
The Murderer says, "Lets shag the cat, set it alight, then break it's neck"
The Necrophiliac says, "Lets shag the cat, set it alight, kill it, then shag it again"
The Sadomasochist says, "Meow"