A German family on their holiday are attacked by a large creature called the Motoshondu, which completely destroys their boat.
The mystery gang are on their holiday; Shaggy and Scooby, of course, eating their snacks, Fred playing volleyball with himself, Velma digging in the sand, and Daphne surf-boarding. Daphne is met by an islander who is also surfing, who wants her to leave the waters to the locals. Suddenly, Daphne is attacked by Motoshondu, who appeared beneath the surface of the water and bit into her surf-board.
Coming to the shore, Velma examines the bite on the surf-board and exclaims that it's bigger than a shark's bite. Although, she denies the fact that their would be a monster in the waters. The German family disagree and say that there is actually a monster lurking in the ocean.
They are taken on a helicopter trip by Sharky, a local, where they investigate the ocean. The are then taken by "Crunchy" on his boat, to get a closer look at an odd formation of rocks where boats have been breached over the years. They are abruptly confronted by Motoshondu and crash into the formation of jagged rocks and their boat sinks. They are saved by Sharky in his helicopter.
The gang decide to invetigate the island and visit Aqua Land. There, they meet Marine Biologist Maura Ravenmane, who explains to them about the wildlife in the waters and how she protects the animals and especially turtles. She claims that being on water would make her seasick. Meanwhile, Shaggy and Scooby become friendly with an Orca as they have some lunch.
When trying to find "Crunchy", they discover his shack empty, but Velma discovers a life jacket with the name Charles Granville and Fred finds a large television screen in the back projecting images of fish and sea-life swimming around. They find a dingy is missing and come to the conclusion that he probably went out to confront the monster by himself and would probably be in a lot of danger.
So, the gang set out with some high-tech equipment aquired from Maura and set out to find "Crunchy". Velma is keen to point out that she didn't come. Motoshondu appears once again and breaks their boat. The gang are forced to investigate underwater with their gear and equipment, which Shaggy and Scooby are reluctant to do.
Underwater, the gang discover a graveyard of wrecked ships, probably brought down by the jagged rocks. Fred hatches a plan using the boat corpses. Because of the monster's size, they are unable to capture it and are forced to head back to the surface. On a large wave, Motoshondu is forcefully beached. When unmasked, the beast turns out to be "Crunchy", or Charles Granville as Velma points out, who'd been controlling a large submarine-like vehicle to help keep the sea-life safe from civilians.
Going back to their holiday home, the gang are ready to finish their holiday, but the next people are ready to move in. The gang are forced to exit.
- Fritz (single appearance)
- Helga (single appearance)
- Fritz and Helga's daughters (single appearance)(no lines)
- Nedley Blake (mentioned)
- Sea turtles (single appearance)(no lines)
- Stink Eye (single appearance)
- Motoshondu (island spirit) (single appearance)(statue)
- Becky (single appearance)(no lines)
- Mr. Keenan (single appearance)
- Mrs. Keenan (single appearance)(no lines)
- Mr. and Mrs. Keenan's son (single appearance)(no lines)
- Mr. and Mrs. Keenan's daughter (single appearance)(no lines)
- Big Blue Mama (destroyed)
|Sharky Tazo||He collected salvage from the wreck of Crunchy Granville's boat.|
|Maura Ravenmane||She wants to protect the animals and especially turtles.|
|Crunchy Granville||Velma discovers a life jacket with the name Charles Granville in his shack.|
|Stink Eye||He thought only the islanders should have the right to surf on the island.|
|Crunchy Granville as Motoshondu||To protect the sea turtles' mating grounds.|
|Frank Welker|| Scooby-Doo|
|Casey Kasem||Shaggy Rogers|
|Mindy Cohn||Velma Dinkley|
|Grey DeLisle||Daphne Blake|
|Jeff Glen Bennett|| Crunchy Granville|
|Mimi Rogers|| Maura Ravenmane|
|Kevin Michael Richardson|| Sharky Tazo|
|"Rockaway Beach"||Credits||The Ramones|
- In this episode, the gang did not wear their normal outfits during the entire episode. For instance, Daphne was wearing a bathing suit and sarong for the rest of the episode. While in another part of the episode, they wore scuba gears.
- The Mystery Machine is not in this episode.
- Daphne's surfboard has the same deco as the Mystery Machine.
- The gang discover an underwater graveyard of ships, which resembles the scene in the Scooby-Doo, Where Are You! episode, A Clue for Scooby Doo.
- The Motoshondu's mechanical innards resembles the inside of the fake Lock Ness Monster controlled by Prof. Fiona Penbrooke, in the later released direct-to-video film, Scooby-Doo! and the Loch Ness Monster.
Animation mistakes and/or technical glitches
- None known.
Inconsistencies/continuity errors and/or goofs/oddities
- Velma is given her goggles back by the monster, after a sea turtle knocked them off. How can she put her goggles back on underwater? There would just be water in them and would be the same as opening her eyes underwater.
- Velma is able to locate things near her without her glasses before diving, despite not being able to tell the difference between Scooby and Motoshondu underwater after her goggle's knocked by sea turtle.
In other languages
|Greek|| Το Θαλλάσιο Τέρας|
Το Τέρας της Θάλασσας Επιτίθεται
Το Θαλάσσιο Τέρας στην Ακτή
| The Sea Monster|
The Monster of the Sea Attacks
The Sea Monster on the Shore
- What's New, Scooby-Doo?: Volume 3 - Halloween Boos & Clues VHS released by Warner Home Video on August 10, 2004.
- What's New, Scooby-Doo?: Volume 3 - Halloween Boos & Clues DVD released by Warner Home Video on August 10, 2004.
- What's New, Scooby-Doo?: Complete 1st Season DVD set released by Warner Home Video on February 20, 2007.
- Scooby-Doo! and the Sea Monsters DVD released by Warner Home Video on March 6, 2012.
- Scooby-Doo! 13 Spooky Tales: Surf's Up, Scooby-Doo! DVD set released by Warner Home Video on May 5, 2015.
|Previous episode:||Series:||Next episode:|
|Safari, So Goodi!|| What's New, Scooby-Doo?|
|A Scooby-Doo! Christmas|