He orders a drink, and while he's drinking, the monkey jumps all over the place, eating everything behind the bar. Then the monkey jumps on to the pool table and swallows a billiard ball.
The bartender screams at the guy, "Your monkey just ate the cue ball off my pool table -- whole!"
"Sorry," replied the guy. "He eats everything in sight, the little bastard. I'll pay for everything."
The man finishes his drink, pays and leaves.
Two weeks later, he's in the bar with his pet monkey, again. He orders a drink, and the monkey starts running around...