The Krabby Patty That Ate Bikini Bottom/Bubble Buddy Returns - S8-E15
Continuity mistake: The giant Krabby Patty eats SpongeBob's shoe and sock in the kitchen. But by the time SpongeBob and Squidward run to the door and are stopped by Mr. Krabs, the shoe and sock have magically reappeared.
Dying For Pie / Imitation Krabs - S2-E6
Continuity mistake: SpongeBob makes Squidward a tear jumper and there is a shot of Squidward sighing. In this shot, we can see no-one standing around the register. In the next shot, Mr. Krabs has suddenly appeared next to it.
As Seen on TV / Can You Spare a Dime? - S3-E5
Continuity mistake: When SpongeBob is making the patties at the end, he puts at least 20 patties on the grill. But just after he takes the buns out of the bag, there are now only 10 patties.
Mermaidman Begins/Plankton's Good Eye - S8-E22
Continuity mistake: When Plankton tries to open the safe, his arms come off. The arms stay on the safe. But when Mr. Krabs approaches the safe in the next shot, Plankton's arms have disappeared from the safe.
The Snowball Effect / One Krabs Trash - S3-E3
Continuity mistake: In "One Krab's Trash," after SpongeBob discovers the drinking hat at Mr. Krabs' yard sale, the two straws are connected to a cylinder with a hole. But when Mr. Krabs says "You were born to wear this hat!" the little cylinder has vanished. Later when SpongeBob is blowing bubbles, the cylinder has reappeared. (00:02:25 - 00:05:00)
Mermaid Man and Barnacle Boy IV / Doing Time - S3-E1
Continuity mistake: When SpongeBob zaps the pickles, he is standing next to the door. He instantly moves to the center of the room in a subsequent shot.
Chocolate With Nuts / Mermaid Man And Barnacle Boy V - S3-E11
Continuity mistake: After MermaidMan screams "To Make Out Reef" he accidentally falls over on his chair. When Patrick complains that they aren't gonna get pizza the chair is back up again.
Culture Shock / F.U.N. - S1-E10
Continuity mistake: When we first see Squidward in the canyon background, his outlining is gone. Then, in the next shot, it's back.
The Secret Box / Band Geeks - S2-E14
Continuity mistake: When the band is marching through the streets, whilst Squidward is pressuring the flag twirlers to move faster, there are some fish drumming behind them. One is a blue fish wearing a yellow shirt seen standing on the left, and another is a brown fish wearing a red shirt seen standing on the right. When the flag twirlers behind to fly off the ground, those two fish have swapped places.
Banned in Bikini Bottom/Stanley S. SquarePants - S5-E20
Continuity mistake: In Stanley S. Squarepants, when SpongeBob and Stanley go see Squidward when he's getting the newspaper, both Squidward and the newspaper change position in between shots.
Club SpongeBob / My Pretty Seahorse - S3-E12
Continuity mistake: In "My Pretty Seahorse", Spongebob is using a spatula with slots in it. Later, when Mystery eats it, the spatula is now completely flat.
Culture Shock / F.U.N. - S1-E10
Continuity mistake: In "F.U.N.", Mr. Krabs sets down the Krabby Patty in front of Plankton. Almost the whole plate is on the yellow part of the table, but when the camera cuts to Plankton, the plate is mostly in the red part of the table. In the next shot, the plate returns to its original position.
Squidtastic Voyage/That's No Lady - S4-E15
Continuity mistake: In "That's No Lady", Patrick runs through Spongebob's wall, leaving a Patrick-shape in his house. Patrick pushes a bit of Spongebob's house, which disappears in the next shot.
Ghoul Fools - S8-E24
Continuity mistake: When Squidward is sucked into "The Void", the bag of money that he was holding vanishes in the next shot.
Summer Job - S7-E18
Continuity mistake: Mrs. Puff didn't know that SpongeBob works at the Krusty Krab, when she already found out in 3-18 "Krusty Love." Even stranger thing, Mr. Krabs and Mrs. Puff have no idea who each other are, but they also already met in that episode.
Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: In "Fools in April", Spongebob is scrubbing the floor and a customer comes up to him to ask for a couple of ice cubes. In the next shot, the water puddle on the floor gets increasingly bigger.
Continuity mistake: In "Jellyfishing" when Squidward gets home from the hospital, Patrick exclaims Merry Christmas! However, later on in the series it is revealed that nobody in Bikini Bottom even knew what Christmas was.
Suggested correction: The episodes are not always meant to be in chronological order. It's entirely possible that "Christmas Who?" took place before "Jellyfishing."
The Bully / Just One Bite - S2-E17
Continuity mistake: In the episode "The Bully," when Flats punches Spongebob, Spongebob states to Gary that he's made out of some spongy material, that it absorbs his blows and it doesn't hurt him at all. But in later episodes, when Spongebob gets knocked out that never happens anymore.
Procrastination / I'm With Stupid - S2-E19
Continuity mistake: Procrastination: When Gary eats all the food, he burps out his bowl. A ladder suddenly appears next to it.