Hypnosis

Hypnosis is a state of mind or a set of attitudes, which is created by a special procedure that is followed. Character on Arthur have been hypnothized, usually in a dream sequence.

Buster's New Friend
Arthur thought Buster was being hypnotized into spending less time with him and more time with his new friend Mike.

D.W.'s Blankie
D.W. thought the dry cleaner machine hypnotized her into giving it her blankie.