SpongeBob's Super Halloween Special (S1E21)

SpongeBob's Super Halloween Special was a 3-day Halloween event starting on October 29th, and ending on Halloween with a super-special new Halloween episode*.

Episodes
Scaredy Pants (Season 1, Episode 13a)

Mermaid Man and Barnacle Boy (Season 1, Episode 6a)

Zombie Sponge (Season 1, Episode 21) (30-minute special)

Zombie Sponge and SpongeBob's Super Halloween Special are the SAME thing.*

(This is not a real event, this is hypothetical... or more of a recreation of the past...)