This is a popular game on a small forum I'm in.The OP there explained it best.
Confused by the title?
Don't worry, we won't corrupt you.... too much.... on purpose. Kidding, kidding. Ever played the Corrupt-a-wish game? Pretty much same thing.
I make a wish, and the next person to post finds an ironic way to derive bad consequences from granting the wish, or to otherwise tag a downside to it, and so on and so forth.
For example:
Bob: I wish to rule the world.
Susie-Ann: Granted. But you did not specify which world. You are now ruler of pluto. I wish I had a fish
Fredrico: Granted. It's a large, man-eating shark. I wish I had a ham sandwich
If a wish is uncorruptable, there are two courses of action: corrupt it anyways, or answer the wish with "not granted".