The main reasons this is one of my Simpsons Halloween favourites?

It reminds me of being a kid. Since the show went into syndication so quickly after it first aired, I remember seeing all of these older episodes over and over again so they're burned into my memory in a way that I hope never gets lost.
I remember actually being a little scared by this at the time. I think it might have been because of James Earl Jones' ascending voice at the end, but still. It felt weird and kind of cool to have a cartoon scare me briefly.
It's gorgeously drawn.

I always thought they got the name for the Halloween specials (Treehouse of Horror) from this specific short and loved that it was based on such a well done episode.