He goes into the bar, and speaks to the owner, who sizes him up, and offers him the job. He adds this: "One thing. If you ever hear, 'Big John's a-comin'', just get out of here as fast as you can!"
He works there for a few weeks, when one day, he's cleaning the place, and there's an incredible commotion outside. People are yelling, screaming "Big John's a-comin! Big Jooooohn's a-comin!"
As he's trying to leave the bar, though, he's knocked over by a massively huge man, riding an even bigger mountain lion, using a twelve foot rattlesnake for a whip! The man rides the mountain lion up to the bar, tosses the rattlesnake into the corner, and bellows out "Gimme a barrel of pickle juice!"
Our young hero goes into the store room and rolls out a barrel of pickle juice. The man rips the lid off with his teeth and drains it all in one gulp, and tops it off with a belch that rattles windows three towns away.
The young man meekly asks "Would you like another barrel of pickle juice?" "Ain't got time!" comes the reply.
Spoiler:

