Continuity mistake: When Patrick is dressed as food for the "monster" in "Wormy," when the butterfly is on P,atrick's butt he spits out the apple in his mouth and it floats to the top of the water helmet. But when the butterfly is on his helmet, the apple is gone.
Continuity mistake: When Gary and Spongebob are waiting at the door, there is a sign behind him that says "pin the tail on the horace" (yes it says horace), and there is one tail hanging up, but when everybody comes in there are suddenly two.
Continuity mistake: During Spongebob's act, he says to the audience, ".I'd like to give a special thanks to my friend Sandy over here" and the spotlight moves from Spongebob to Sandy. A few shots later, when Spongebob is talking to Sandy, the spotlight is suddenly no longer on Sandy. Then when Spongebob yells "Am I right?" to the audience, the spotlight is on him and as he turns to talk to Sandy again, the spotlight is altogether gone; it's not on either one of them.
Continuity mistake: When Squidward starts making pink bubbles with messages, he goes to his backyard. Notice he never closed the back window of his house. When he starts laughing because of the messages, suddenly the window is closed. After Patrick saves Squidward, the window is still closed, but when they go to the front of his house, the window is open.
Continuity mistake: Gary leaves big saliva trails. When Squidward realizes that Gary leaves these saliva trails, we can see that is a trail in front of Squidward's house. When Squidward tells SpongeBob about these trails in the language of the past, we can see that the trail of the saliva has changed: it bigger and almost in all the scenery. After a while, we see that the road goes directly to Squidward's house, to its door. How did the road change, if we haven't seen Gary moving?
Continuity mistake: When Spongebob shows Patrick the good noodles chart all the stars are wildly scattered in each row. When Patrick is trying to announce his name to the class they're all in a neat row. When Mrs. Puff is removing the star from Spongebob's row they're scattered again.
Continuity mistake: In "Squid's Day Off" Squidward gets mad at Spongebob for ringing a bell over and over again. It shows the bell in the window to the left. Later, when it shows Squidward throwing the cash register onto the ordering desk, the bell is gone from the window. In the next shot of Spongebob, the bell is back in the window. Then, when Squidward shouts "No." the bell is gone again.
Continuity mistake: When Spongebob is outside, and he takes out his "to do list" at first he is holding it with his right hand, but when it shows the front of the paper, you see that it is his left hand. Then it is his right hand again.