Continuity mistake: In the scene where SpongeBob has given his pants to the clam, two continuity errors appear. First, Patrick puts his head in the pants and he says that the clam is hungry. A lot of holes are in his head. In the very next shot, the holes are gone. This is really obvious. The other continuity error is that before Patrick gets those holes, SpongeBob isn't with his pants. When he tries to give the Patty to the clam, he's suddenly with his pants, when the little clam is supposed to have his pants.
Continuity mistake: When Spongebob has melted from stress and exhaustion, he is trying to talk and Sandy tells him to "hold that thought", and you can see the bike that they were riding, in the background. When she makes the fly fishing joke, the bike is gone, and there is a small plane. A few shots later the plane is gone as well.