Mermaid Man and Barnacle Boy / Pickles - S1-E6
Audio problem: When Bubble Bass runs out of the Krusty Krab he is gasping and panting, but his mouth stays closed, his mouth doesn't even open a centimeter.
Mermaid Man and Barnacle Boy / Pickles - S1-E6
Continuity mistake: At the beginning of "Mermaid Man and Barnacle Boy", when SpongeBob and Patrick are watching TV viewing Mermaid Man and Barnacle Boy show, you can see that these heroes have 5 fingers on their hands, as the real human beings. However, when SpongeBob and Patrick meet these heroes, as in the rest of the show, you can see that now, the heroes, have 4 fingers on their hands, as cartoon characters usually have.
Mermaid Man and Barnacle Boy / Pickles - S1-E6
Continuity mistake: In the episode "Pickles", there is a large fish named Bubble Bass. Although his name is Bubble Bass, the captions say his name is Bubble Bath. It is clear that Spongebob is saying "Bass" not "Bath", and his name is given as Bubble Bass in SpongeBob's Diner Dash.
Mermaid Man and Barnacle Boy / Pickles - S1-E6
Continuity mistake: Mermaid Man and Barnacle Boy: Mermaid Man wears green tights, but after SpongeBob absorbs the water ball like "some kind of evil sponge," when Mermaid Man and Barnacle Boy start doing the dog paddle, Mermaid Man's tights have vanished in this shot.
Mermaid Man and Barnacle Boy / Pickles - S1-E6
Continuity mistake: Mermaid Man and Barnacle Boy: When Barnacle Boy opens the box with the two rings inside, in the closeup the "B" ring is on the left and the "M" ring on the right, but in the wideshot Barnacle Boy removes the ring on the left (the "B") and places it on Mermaid Man's finger, then in the next shot we see it's the "M" ring, before both rings vanish.
Mermaid Man and Barnacle Boy / Pickles - S1-E6
Continuity mistake: Mermaid Man and Barnacle Boy: When SpongeBob and Patrick (dressed in their superhero costumes) exit the pineapple the front door opens at the right side (outward), but after getting on Squidward's nerves, when they retreat back inside the front door opens the opposite way at the left side (inward).
Mermaid Man and Barnacle Boy / Pickles - S1-E6
Other mistake: In the end credits for the episode "Pickles", Bubble Bass is named "BubbleBass" (without a space).
Answer: I believe this is the Season 6 episode "Spongicus".