Well, do you know what cotton is? It's like that, but really sugary! ...Actually, I guess I could've just said it's like cotton - that'd make more sense.

Not much, really - the ones on my planet can't grant the same wish twice, and they can't kill someone stronger than the guy who made the Dragon Balls. [Which he wouldn't do anyway, though by the time they found out about that rule, every villain fell into that category.]