Does anyone remember this segment from Sesame Street?

Does anyone remember a segment on Sesame Street where a boy is afraid of the dark and his dog is on the floor casting shadows on the wall (that look like an alligator) to scare him further? He keeps calling his parents in to his room but they don’t believe his story. This goes on several times until he realizes that it’s the dog on the floor. I believe it was a cartoon. I have told several people about this little vignette but nobody seems to remember it. If it’s online somewhere I would love to see it again too.