Guy walks into a bar and sees a huge jar of ten dollar bills. He asks the bartender what's with the tip jar and is told that it is an ongoing bet. Put ten dollars in the jar, complete three tasks and walk away with all the money - which appeared to a few hundred thousand.
Of course he wants to know what the three tasks are and is told:
First you have to drink down an entire bottle of tequila worm and all without taking a breath or making a face.
Second, you have to go outside where you will find a very nasty bulldog with a bad tooth. Remove the bad tooth.
Last, there is a 100 year old woman upstairs who hasn't had sex in 40 years. Satisfy her and the money is yours.

The guy thinks it over and after a few shots of whiskey it seems doable. So he puts his $10 in the jar, grabs the tequila and downs it worm and all. Although he is ready to choke, he doesn't make a face and so completes the first task.
Then he staggers drunkenly out into the yard where he finds the bulldog. Inside the bar they can hear the growls, yelps, screams of pain until at last the guy walks in, looks around triumphantly and asks "Now where is the old lady with the bad tooth?"