For Halloween, the Sesame Street friends all dress as witches. As the "trick" part of "trick or treat," they make people guess which witch is which. It works like a charm until Oscar the Grouch hilariously turns the tables on them with his own Halloween trick. This warm, funny story also teaches the powers of observation.Muntean, Michaela is the author of 'Which Witch is Which?', published 2004 under ISBN 9780375827822 and ISBN 037582782X.