A man saw a dog tied to sign entitled "talking dog for sale: ten dollars". He stops to enquire, and on a whim, asks the dog, "So can you really talk?"

"Yes", the dog replies, "I was experimented on in 1940 by an elite group of Nazi scientists. I got away and hopped on a ferry to America, but not before biting Hitler. I now work part-time for the FBI"

The man, amazed, runs to the front door and gives the owner of the dog his $10. Before walking away, the man, overcome by curiosity, finally asks "how come you're selling him so cheap?"

"Because", his owner replies, "he's a <snip>ing liar."