Survival of the Idiots / Dumped - S2-E8
Continuity mistake: In Dumped, when Patrick is finished brushing his teeth, his toothbrush disappears.
Something Smells / Bossy Boots - S2-E1
Continuity mistake: When Spongebob jumps on a car and asks "am I ugly", and the guy blows up his car, you see his car has small little wheels. When one of the wheels bounces on Spongebob, it is huge.
Your Shoe's Untied / Squid's Day Off - S2-E2
Audio problem: In "Your Shoe's Untied" when Gary ties Spongebob's shoes he says "hoppin' clams where'd you learn to do that?" When he says "clams" his lips are out of sync.
Something Smells / Bossy Boots - S2-E1
Continuity mistake: In Something Smells, when Spongebob finishes eating the sundae and he comes out of the room and drops his spoon. He turns to his right, the spoon that he dropped has disappeared.
Something Smells / Bossy Boots - S2-E1
Continuity mistake: In Something Smells, once Spongebob finishes saying hello to all the band people, he says "Is it something I said?". You see him start to walk back but when you see a close up of him, a fire hydrant appears.
Pressure / The Smoking Peanut - S2-E12
Continuity mistake: In The Smoking Peanut, when Spongebob and Patrick are running in to see the oyster, Patrick is on the right, but in the next shot, he's on the left.
Big Pink Loser / Bubble Buddy - S2-E3
Continuity mistake: Bubble Buddy: When Spongebob brings his Bubble Buddy to the Krusty Krab, Squidward's restaurant hat is visible on his head. It is not seen when he looks into Bubble Buddy when he says, "That Bubble Buddy sure looks good."
Pressure / The Smoking Peanut - S2-E12
Continuity mistake: Patrick's popcorn disappears completely after he drops it.
Something Smells / Bossy Boots - S2-E1
Continuity mistake: In Something Smells, when Spongebob is making the sundae, when he says "This sundae is gonna taste great" he has one spoon in his hand, but when he turns around, he has 2 spoons.
Something Smells / Bossy Boots - S2-E1
Continuity mistake: In Something Smells, when Patrick is helping Spongebob outside with the "mirror test", he pulls out the mirror and you see his face to the side of it. In the next shot he is completely behind it.
Mermaid Man and Barnacle Boy III / Squirrel Jokes - S2-E4
Continuity mistake: In Squirrel Jokes, when Spongebob comes out for his second act, there's a back shot of a crowd, and there is one guy in the front right (from the back view) who is green. There is another front shot of the crowd and the guy completely disappears.
Your Shoe's Untied / Squid's Day Off - S2-E2
Continuity mistake: Spongebob says, "We forgot to change the close sign to open," yet when Squidward walks out throughout the episode there is no sign at all.
Continuity mistake: When Tom and Fred are outside the Krusty Krab, Tom is light green, but later in this episode he is dark green. For more info on Tom: http://en.spongepedia.bimserver.com/index.php?title=Tom For info on Fred: http://en.spongepedia.bimserver.com/index.php?title=Fred.
Your Shoe's Untied / Squid's Day Off - S2-E2
Continuity mistake: When SpongeBob is sad because he can't tie his shoes, you see is night. When Gary ties his shoes, suddenly it becomes day.
Mermaid Man and Barnacle Boy III / Squirrel Jokes - S2-E4
Continuity mistake: In "Squirrel Jokes", SpongeBob wants to make a joke about a fork. Someone screams "Forks?" and SpongeBob becomes more nervous. After that, the fork disappears from where it was.
Your Shoe's Untied / Squid's Day Off - S2-E2
Continuity mistake: In "Squid's Day Off", sometimes Squidward's house door opens to the left, and sometimes opens to the right.
The Bully / Just One Bite - S2-E17
Continuity mistake: In "Just One Bite," when everyone says "The only people who don't like Krabby Patties have never tasted one," the kitchen doesn't have a back door. After Squidward says "I gotta have more," he looks in from the back door.
Grandma's Kisses / Squidville - S2-E9
Continuity mistake: In Squidville, Spongebob and Patrick are at the front gate and when Spongebob says, "But you just ate 3 orders of fried oyster skins," Spongebob's teeth disappear.
Survival of the Idiots / Dumped - S2-E8
Continuity mistake: In "Dumped", when Gary takes Patrick's cookie they are in the laundry room. When SpongeBob wants to take Gary for a walk, they instantly appear in the living room. SpongeBob also has a leash in his hand. There is no time for them to walk from the laundry room to the living room.
Pressure / The Smoking Peanut - S2-E12
Continuity mistake: When Sandy and SpongeBob are climbing the mountain at the beginning of "Pressure," when Sandy pushes the rocks down at SpongeBob, there were two big ones holding them that vanish. You could say that she pushed them down too, but remember that they were different colours than the smaller ones. (00:01:40)
Answer: I believe this is the Season 6 episode "Spongicus".