Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: When Spongebob grabs Squidward's legs you only see him grabbing at two of Squidward's legs and the other two legs have disappeared, but when the shot changes they're back again.
Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: In "Neptune's Spatula", Patrick takes a picture of SpongeBob holding the spatula. When this happens, we can see that SpongeBob is a little worried because clouds have appeared there. However, after a while, Patrick shows the picture to Neptune, and we can see that in the picture SpongeBob is smiling and pointing with the spatula.
Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: Eventually after Spongebob takes the door wheel handle off, it comes back.
Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: Fools in April: While Squidward is having difficulty apologizing to SpongeBob, they're both standing in front of the pineapple with its front door wide open inward, but when Squidward places the bubble over his head the front door is suddenly wide open outward, so Squidward could slam the door.
Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: In "Fools in April", Squidward put some paper towels in his ears to block out the noise of Spongebob's laugh echoing throughout the Krusty Krab. He covers his ears, and in the next shot, the paper towels are missing and not in his hands.
Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: In "Fools in April", Gary is sleeping next to his food bowl in the first shot, with Spongebob's bed nowhere to be seen. After hearing Spongebob's voice, Gary wakes up. In the next shot, Gary's food bowl is sitting in front of Spongebob's bed post.
Fools in April / Neptune's Spatula - S1-E19
Continuity mistake: In "Fools in April", Spongebob is scrubbing the floor and a customer comes up to him to ask for a couple of ice cubes. In the next shot, the water puddle on the floor gets increasingly bigger.
Answer: I believe this is the Season 6 episode "Spongicus".