A bloke went to his mate's fancy dress party with nothing but a naked girl on his back.
"So what the heck are you supposed to be?" the host asked.
"I'm a snail." The bloke replied.
"What a load of rubbish!" the host spat. "How can you be a snail when all you've got is that naked girl on your back?"
"That's not a naked girl, mate," the bloke replied,