On Halloween night two little black children, a sister and her little brother, dressed in costume and went out trick-or-treating.
Their first stop was the house of crabby old white man, Mr. Smith. They rang the door bell. Mr.Smith answered and they shouted "TRICK OR TREAT". Sourly Mr. Smith looks at them and ask, "Just what are you supposed to be?". The little black girl answers, "Were Hansel and Gretel". "No way", says Mr. Smith "Hansel and Gretel were white. Come back when you get it right." With that he slams the door in their face.

Not to be out done the two little black kids go home and change costumes. Again they ring the door bell at Mr. Smith's house and shout "TRICK OR TREAT" as Mr. Smith opens the door. "Now what are you supposed to be?" he ask. The little black girl answers, "Were Jack and Jill". "I don't think so.", replies Mr. Smith "Jack and Jill were white. Don't come back until you get it right."

Again he slams the door in their face and again the two black kids go home and change costumes. For the third time the little black kids ring the door bell and shout "TRICK OR TREAT" as Mr. Smith answers. He is in total shock to find the black girl and her little brother totally naked. " What is this?" he ask. The little black girl declares," Were chocolate M&M's, I'm plain (then pointing to her brother) and He's with nuts".

48 years ago in first grade, I heard a variation on that joke:
Black man rejected from costume party becuase George Washington was not black. He returns with a 2x4 shovved up his ass, and comes as a fudgesicle.

There once was a young man named Cole.
Whose humor was really quite droll.
He went to a Ball
dressed in nothing AT ALL!
And backed in as a Parkerhouse roll.