A guy is walking past a house and sees a sign saying "talking dog for sale"
he naturally goes to have a look and goes round to the back yard, where the dog is tied up.

"Can you really talk?" he says to the dog (feeling stupid)

"yep" says the dog

"how come?, ive never seen a talking dog before" says the guy

"well ive been talking since i was a pup, ive worked as a special agent for the police, the army, MI5..ive travelled the world twice over, ive starred in movies, and now im just living out the rest of my life, nice and quietly, trying settle down a bit....

The man was amazed, he went to the house and knocked to speak to the owner.

"How come you want to sell such a special dog?"

The man replied:

"Coz he's a damn liar, he's never done any of that shit"

lol.