After Velma wins a contest for the best invention, the gang travels to Tokyo, Japan. When a mystical shaman zaps a pizza with a monster-transformation spell, Shaggy eats it. Shaggy starts to grow into a Godzilla-like monster whenever he goes to sleep and he starts eating everything in sight. Now the gang is running around Tokyo trying to get away from the police who want to capture Shaggy.
This episode contains examples of the following:
- Attack of the 50-Foot Whatever: The monster is "Shag-Zilla", a Kaiju-fied Shaggy... except it's a hoax, as usual.
- Back Blocking: When a bunch of angry Japanese villagers is crowding around the gang, one of them in a light grey shirt fills the screen.
- Character Catchphrase: Exploited. Shagzilla's speech only consists of roaring "Zoinks!". When citizens hear Shaggy yell his catchphrase, they assume he's the monster.
- Clothing Damage: When Shaggy first wakes up, his nightshirt is ripped and torn, as if they burst when he grew into a giant. Turns out they were actually ripped up by Dogbot.
- Enlightened Antagonist: The Ancient One is a ghost who looks like an old wizard, and who demands that the scientists at a Tokyo factory abandon their plans for a new wharf because it would be a threat to the simple traditional Japanese way of life. The ending implies that he might be Real After All, and the scientists eventually decide to respect his wish.
- Failed a Spot Check: For some reason, no one, not even Velma points out that since Shaggy still had his leg chain after the monster's rampage, he couldn't have been responsible because the monster wasn't wearing a chain. Also one for the villain as well, since he had Dogbot bite through the chain, instead of just taking it off.
- Humongous Mecha: It turns out that Shagzilla is actually a giant robot made up to look like a kaijufied Shaggy.
- Implacable Man: Once the Japanese police decide to try to arrest Mystery Inc, they send Lt. Tanaka on the case. Nothing seems to be able to get her off their trail- even when they board a bullet train, Tanaka is following them via helicopter moments later.
- Maybe Magic, Maybe Mundane: The Ancient One. Considering he isn't brought up when the actual villain of the week is arrested, everyone is left wondering if he was a hoax by a third party or if he was a ghost who wanted the factory to be moved. Whatever he was, he got his wish, so it became a moot point.
- Notzilla: The monster of the week is a giant monster named "Shagzilla", supposedly Shaggy cursed to transform into a Godzilla parody at night. Actually, it's a giant robot built by the villain of the week, and Shaggy is duped into believing he is the monster because, while he is asleep, he is made up as the monster and placed on a Tokyo maquette.
- O.O.C. Is Serious Business: When Shaggy wakes up the first morning after Shagzila's appearance, he half-heartedly comments that he doesn't feel up for breakfast. Not only are the Gang shocked, even Shaggy himself is in disbelief that he actually said that.
- Paper-Thin Disguise: Daphne is able to create disguises for the gang with a stapler and mascura when they go to meet Professor Pomfrit. Unfortunately, they aren’t really that good and the police see right through them when they arrive.
- Pet the Dog: Despite their rivalry, Velma gives Dogbot to Elliot. Elliot, who finally has a dog that he's not allergic to, is grateful.
- Robot Dog: Velma's newest invention, Dogbot, is a fully-autonomous canine that doubles a Superpowered Robot Meter Maid. At first, Scooby feels jealous of the machine, but by the end, Velma makes it clear that no machine could replace him.
- Stating the Simple Solution: It's mentioned that if Shaggy is cursed to become a Godzilla monster and rampage through the city, either he could turn himself in to the police and they could watch him see if he's the suspect while lawyering up to prevent possible framing. The gang vetoes that by running away from the officer wanting to take them into custody, and deciding to go on the lam. It turns out that was the right call since Velma's professor was framing Shaggy while getting revenge against Dr. Onodera.
