It's very simple, the person above wishes for something & you have to grant it. Problem is, it has to go badly, creatively wrong .

I'll start. I wish I was 5'10" tall & model thin.

* Your wish is granted...you just tripped over one of the elves at the Mall cuz you didn't see him & now he's suing

*Edit* After you grant the wish, you make one of your own & the game continues