Other mistake: In the episode where SpongeBob has to do 3 things in 1 night, near the end, they all get frustrated for not doing their tasks. Look at Mr. Krabs. He runs over to SpongeBob and behind him is bubbles. Impossible, because in Sandy's dome is air.
Continuity mistake: Plankton's size changes drastically throughout Krabby Road. Plankton can be seen as reaching up to Spongebob's waist at one point. When he's clutching to the neck of a guitar, the amount of frets that go into his height change between one, two, three, and five, depending on the shot.
Continuity mistake: In "Pineapple Fever", Spongebob re-scrambles the jigsaw puzzle right in front of him and Squidward runs outside. In two shots, when Squidward returns, the jigsaw puzzle pieces have moved to the left on the screen, almost behind Spongebob.
Continuity mistake: In "Chum Bucket Supreme", Patrick is painting the slogan "Krabby Patties Are Fum" on the Krusty Krab with no hole in the back of his head. In a few shots, Patrick is standing in the same spot, and the hole in his head has reappeared.
Continuity mistake: In "Chum Bucket Supreme", Mr. Krabs hears the sound of Plankton's cash register, and the wide shot shows him standing on the pavement around the Krusty Krab. In the next shot, he is now standing in sand.
Continuity mistake: In "Giant Squidward", Squidward goes to spray his wilting kelp with fertilizer and sets down a watering can right next to him. When the kelp goes back to normal in the next shot, the watering can disappears and is not seen again.