A man is driving down a highway in the country. He passes a sign that says
“Talking Dog for 5 Dollars”
Interested, the man goes to the house. Suddenly a dog walks up to him and says
“Hello!”
Mind blown, the man says
“Wow! You can talk!”
Then the dog says
“Yes indeed! I also helped Einstein with his theory of relativity, was a professor at Yale, and worked for the FBI!”
The man then knocks on the door and a farmer comes out. The man says
“I would like to buy your dog! But just one question. Why is he only five dollars?”
The farmer then says
“Because the dog is a freaking liar!”