WMG / SpongeBob SquarePants S 1 E 14 "SB-129" / "Karate Choppers"

The events of the episode are undone by Squidward himself after the episode ends.

When Squidward returns to the present at the end of the episode, his earlier self should still theoretically be stuck in the freezer at the Krusty Krab. Therefore it’s not too much of a stretch to assume the Squidward that time-traveled eventually went to the Krusty Krab and let his other self out, at which point the former Squidward ceased to exist.