Does your bartender keep a tab? (joke)?

A guy walks into a bar to get some drinks before he calls it a night. He notices a huge jar of money that the bartender is paying very close attention to. He asks what the money is for. "A challenge," replies the bartender. He asks what the challenge is. The bartender replies, "Knock out the bouncer, **** that fat lady over there, and give the dog downstairs a rabies shot and I'll give this jar to you." "Hell no," replies the man. He forgets about it and has a few more beers. Completely smashed, he realizes he doesn't have enough money for the taxi ride home. He asks the bartender what he has to do for the jar. He knocks out the bouncer and goes downstairs, not coming back for a full 20 minutes. The bartender hears yelping the whole time, and when the man comes back up, he's zipping up his pants. He walks over to the bartender and asks, "Now where's that woman you wanted me to give a rabies shot?"