Video: See the puzzle guess that caused Pat Sajak to walk off set

Pat Sajak walked off the "Wheel of Fortune" set after two contestants began shooting off absurd answers about horses.

It all happened during Monday night's show. There was just one letter on the board -- 'N' -- and the category was "What are you doing?"

One contestant guessed, "Riding a brown horse," which was wrong. Then, another contestant said, "Riding a white horse," which was also wrong.

After the second guess, Pat jokingly walked off set before saying "Who said anything about a horse?!"

The final answer was “seeing a buddy movie.”