SpongeBob's House Party (aka Party Pooper Pants) - S3-E10
Continuity mistake: When Spongebob comes home after being arrested, he picks a spare key up from under his mat and gets angry at himself for trying to break in the night before. When he walks in, discomfort on his face, the mat is gone.
SpongeBob's House Party (aka Party Pooper Pants) - S3-E10
Continuity mistake: Patchy's hook hand disappears when he is playing the accordian.
SpongeBob's House Party (aka Party Pooper Pants) - S3-E10
Continuity mistake: When Spongebob comes home from the police station in the morning, he gets the spare key from under the mat. That mat definitely wasn't there last night.
SpongeBob's House Party (aka Party Pooper Pants) - S3-E10
Continuity mistake: When Patchy the Pirate is flying through the houses, he finally hits a pole with nothing on him. Yet when Patchy comes screaming back into his hat, he had a broken window in him and wood through his hat.
SpongeBob's House Party (aka Party Pooper Pants) - S3-E10
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.
SpongeBob's House Party (aka Party Pooper Pants) - S3-E10
Continuity mistake: When SpongeBob is locked out of his house, he digs a hole to try and get in. This hole doesn't exist the next morning.
Answer: I believe this is the Season 6 episode "Spongicus".