Which simpsons episode was it...?!

when bart was up all night watching tv and he goes to school the next morning and he can't pay attention in class because of all the tv characters dancing around him!? and the guy with the clockhead says, "It's finally happening, Bart!. You're losing your mind!" it was hilarious! can you tell me which episode that was so I can look it up on youtube!? THANX!!!Www@Enter-QA@Com

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