Lady: Who are you two supposed to be?

Kids: Hansel and Gretel

Lady: You can't be Hansel and Gretel, they're white.

So the kids went home and changed and went back to the lady's house.

Lady: Now who are you supposed to be?

Kids: Jack and Jill.

Lady: You can't be Jack and Jill, they're white.

Then the kids went home to change again but went back to the lady's house with nothing on this time.

Lady: What are you supposed to be this time?

Kids: Hershey bars, one with nuts and one without.