SpongeBob and Patrick are at a Mermaid Man and Barnacle Boy fan club meeting, where they learn that a new movie will be made based on the heroes, and meet the actors who will be portraying them. SpongeBob is offended that the movie is using actors instead of the real Mermaid Man and Barnacle Boy, and tells the fan club that they must boycott the movie. Then he and Patrick are thrown out of the building. The two then go to Shady Shoals and tell Mermaid Man and Barnacle Boy that Drippy Brothers Studios is making a movie about them and using actors. The heroes find the news horrible, and Patrick suggests they make their own movie, which they agree with. After brainstorming ideas at the Krusty Krab, SpongeBob and the crew meet to make the movie. SpongeBob is the director and in charge of the movie, Squidward, the makeup artist, prepares the actors for the movie, Sandy is in charge of using the dynamite for explosion scenes, Patrick is the cameraman, Mr. Krabs caters the crew with Krabby Patties, Pearl is the leading lady and the Invisible Boatmobile, and Mermaid Man and Barnacle Boy, of course, are the stars of the movie. While they are filming, Plankton appears to audition for Man Ray, but SpongeBob tells him that Man Ray isn't in their movie. Plankton is given the job of working the microphone instead. Mermaid Man has trouble with one of his lines and it takes 5,003 takes to get it right. A scene is filmed where Mermaid Man and Barnacle Boy ride Pearl up a steep mountain to Kelp-Thing's hideout. Pearl is too heavy to pull, and slides down the mountain, crashing into the sets. Everything is destroyed, and Patrick reveals that he had been filming with the lens cap on, meaning that they have no footage. SpongeBob goes berserk with frustration, but Mermaid Man convinces him to finish the movie. Mr. Krabs holds the premiere of SpongeBob's production in his restaurant, hoping to make lots of money from the movie. The members of the Mermaid Man and Barnacle Boy Fan Club attend, but only because the Drippy Bros. production is sold out. The movie is then shown. SpongeBob plays with a car near a box with "Lox" on it. Then the patty vault is opened and Kelp-Thing comes down, but then Mermaid Man (as Sandy) attacks him. He and Barnacle Boy unite. Then it ends. The movie proves to be terrible, and the fans are not pleased. However, Mermaid Man is glad that SpongeBob proved he and Barnacle Boy still have some "action" left in their old bones. They then laugh happily due to their efforts.
This episode is number 14 in Tom Kenny's Top 20 on iTunes. His description says:
"When SpongeBob's heroes are considered too 'old' to portray themselves in a Hollywood-type movie, he decides to make his own. As a comic book fan, I've sat through horrible movies based on classic comics, wishing I could 'do it right!'.
"Mermaid Man and Barnacle Boy VI: The Motion Picture" was ranked #53 during the Best Day Ever event on November 9–10, 2006.
As of August 11, 2016, The Internet Movie Database (IMDB) gives this episode a rating of 8.1/10 based on 173 ratings by users. TV.com users give this episode a 8.1/10 based on 226 votes.
Running Gags: When someone says "boom" in a sentence, the scene changes to Sandy preparing to use a detonator, with Mermaid Man and Barnacle Boy in the background. She asks "Did somebody say boom?" and pushes the detonator. Mermaid Man and Barnacle Boy blow up. Also, a close-up of SpongeBob's mouth saying "actors" using a live action human mouth.
During a tribute to Ernest Borgnine, this episode was skipped. However, it was paired with "Mermaid Man Begins."
This is the only episode out of the six original Mermaid Man and Barnacle Boy episodes to not have the black and purple fish scale background on the title card. It is also the first one to have a subtitle.
The closeup where SpongeBob says "actors" has become subject to edits on YouTube.
The leader of the Mermaid Man and Barnacle Boy Fan Club is one of the nerd fish from Weenie Hut Juniors.
This is the last episode of the "Mermaid Man and Barnacle Boy" sub-series.
In Polish version, the narrator mistakenly reads title as Mermaid Man and Barnacle BoyIV: The Motion Picture instead of Mermaid Man and Barnacle BoyVI: The Motion Picture.
During almost all of the filming, the lens cap was not on the camera.
When the Mermaid Man and Barnacle Boy Fan Club was coming to the Krusty Krab and before the movie, the Fan Club kids were the same. After the whole movie, most of the Bikini Bottomites are in the seats.