SpongeBob Meets the Strangler / Pranks a Lot - S3-E20
Plot hole: In the end of "Pranks A Lot" SpongeBob and Patrick glue the door shut in order to keep Mr. Krabs inside the Krusty Krab. When SpongeBob And Patrick are visible again, it turns out that a lot of customers have entered the Krusty Krab to see SpongeBob and Patrick naked. All of those people had no way to get into the Krusty Krab with the doors glued shut. It can't be that they broke down the doors, as they're still there.