Panda...
A panda walks into a cafe. He orders a sandwich, eats it, then draws a gun and proceeds to fire it at the other patrons. "Why?" asks the confused, surviving waiter amidst the carnage.
The panda pauses on his way out, produces a badly punctuated wildlife manual, and tosses it over his shoulder. "Well, I'm a panda," he says at the door. "Look it up." The waiter turns to the relevant entry and, sure enough, finds an explanation:
"Panda. Large black-and-white bear-like mammal, native to China.
Eats, shoots and leaves."
(Yes ok, I'm getting me coat)