It's the time of the Old West.
A citizen of the town comes running into the saloon and screams, "Big Bad Bart is coming! Big Bad Bart is coming! We gotta get outta town."
Everyone gets up in a hurry and takes off as fast as they can, including the saloonkeeper, who when hopping over the bar slips on a beer and knocks himself unconscious.
When he comes to, he makes his way outside to see the biggest, meanest man he's ever seen riding down the center of the town on two buffaloes, whipping them with a rattlesnake screaming, "Giddyup! Let's go, come on."
He makes his way over to the saloonkeeper, dismounts, and enters the saloon.
Breaking both doors off the hinges while entering, he walks up to the bar, slams his fist down, breaking the bar in half and hollers, "Gimme some beer in a gallon jug."
After the saloonkeeper hands him the jug, he watches as the man drinks it in three seconds flat.
When he's done with his drink, the man turns around to walk out the door.
The saloonkeeper couldn't believe his eyes and wanted to see him do it again. He asks him, "Don't you want another beer?"
The man turns around and says, "Heck no, Big Bad Bart is coming! I gotta get outta town!"
