Season 3 Episode 9 Who Was That Cat Creature I Saw You With Last Night The gang visit Daphne's aunt, Olivia Dervy, who lives in New York. On the way to her apartment, they witness a robbery in a jewelry store. Scooby falls down into the sewer and sees a strange cat-like creature carrying an armful of expensive jewelry. They head to Olivia's apartment, where she tells them she has been suffering from terrible nightmares. A few weeks ago, she received a cat medallion in the mail, and began having dreams ever since. She dreamed she turned into a cat creature and began to commit robberies. They call her doctor, Dr. Bell, to give her some prescriptions. After that, the gang decide to investigate who sent Olivia the package, along with the robbery in the jewelry store. Shaggy and Scooby discover the package was sent from a cemetery, where they find the crypt where the cat creature lies. Meanwhile, Fred, Velma, and Daphne, discover that there is a trap door in the jewelry store that leads to the cemetery. The gang meet up in the cemetery and head back to the hotel, where Olivia has had another nightmare. Also, there are wet paw-prints leading from her window to her bed, convincing her that she is really transforming into a cat creature. The gang devise a scheme to catch the cat creature; they eventually catch him after Scooby-Doo leads him on a harrowing elevator ride, Fred unmasks the cat creature only to find out that it was actually Dr. Bell. Bell used the cat medallion to hypnotize Olivia because of her effective response to hypnosis, so he could pin his robberies on her and escape with millions of dollars worth of stolen jewelry, while keeping the more valuable gems for himself, like the Richmond Ruby. The gang knew it was Dr. Bell, because the handwriting on the package for the cat medallion matched the writing on the prescription that he gave to the gang. Olivia asks about Shaggy's disappearance. Velma says that the room is filled with secret rooms and panels, and demonstrates by pressing one, revealing that Shaggy was sound asleep! Scooby is overjoyed that his owner is safe, and begins showering him with kisses, but the moment is ruined when the room starts spinning too fast, throwing Shaggy and Scooby out the window! Olivia asks what they're doing, Shaggy tells her that he and Scooby are just hanging around (literally).

The gang head to China, where they get lost and find themselves in the city of Rampoo. The city is famous for its legend of the moon monster, a creature who came to earth from a moonbeam, and turned everyone he cast his shadow on into stone. The Mystery Machine gets a flat tire, and the gang wind up spending the night at the Rampoo Palace, where they meet Kim Chow Ling, the new owner of the palace, his uncle, Chin Wong Sing, and Ling Foo. Shaggy and Scooby claim to have seen the legendary moon monster, but the rest of the gang dismiss it. The gang learn that Kim will soon inherit his family's fortune. Ling Foo reminds Kim that the treasure must be disposed of, because if not, the moon monster will wreak havoc on everyone at the palace (according to legend). Later that night, the Moon Monster begins to chase Shaggy and Scooby. They narrowly escape, but not before Velma spots the Moon Monster, rowing away in a san pan. The gang and Kim then hear the dinner gong being wrung by Uncle Chin, making it odd since it is two in the morning. They discover Uncle Chin has been turned to stone and the Moon Monster stands behind him. The monster disappears, and Velma finds the first clue, grease streaks behind the statue of Uncle Chin, leading into the wall. They search Uncle Chin's room, and discover ancient tools; one carving tool in particular looks recently used, another clue. The Gang split up, and looks for clues. Velma, Fred, and Daphne row out onto the bay to discover a nearby sea cave. It is there they find a tunnel that leads back to the palace. They realize what is going on, and decide to trap the moon monster. They tell Kim to bag up the family treasure and throw it into the bay. He does so, and the treasure washes up to the nearby sea cave. The gang take the tunnel to the cave, where they discover the moon monster grabbing the treasure. They trap him, and unveil who the moon monster really is: Uncle Chin. Kim is confused as to why would his uncle try to scare him. Back at the Palace of Rampoo, the gang explains it was for the treasure. Fred tells Kim that Chin wanted to get the inheritance away from Kim, so he used the legend of the Moon Monster to frighten him out of his legacy. Kim's confused, since they saw Chin turn to stone by the Moon Monster. Velma tells Kim that he's wrong. Actually, Chin was in the Moon Monster disguise. Kim rang the gong and when everyone got to Chin's room, it looked like he was turned to stone. Kim asks about the statue, Daphne tells him that his uncle carved the statue of himself with the ancient carving tool. Velma explains that the tool was scratched and dull, unlike the rest of Chin's collection, indicating it was used recently. Fred says that the grease marks on the floor was where Chin pushed the statue out from the secret panel when everyone got to his room. Ling Foo tells Kim that he shouldn't have been fooled. Kim admits that they were all fooled. Velma continues saying that Chin knew that the tides would wash anything in the bay into the cave. So all Chin had to do was to scare Kim into throwing his treasure away and be there to get it when it washed up. With the case solved, Ling Foo suggests that everyone gives a good night's rest. Kim, however suggest a snack. Scooby and Shaggy thanks Kim and runs for the kitchen to make giant sandwiches with every Chinese ingredient. When they finished making the sandwiches, Scooby realizes he can't fit the super stretcher sandwich in his mouth. Seeing his owner tie the sandwich down to compress it, Scooby follows suit. As Shaggy eats his sandwich, Scooby says "Scooby Dooby Doo" as he eats his. However, Scooby's neck begins to strength, much to Shaggy's shock! Kim comments that Scooby's eyes are bigger than his stomach. Daphne corrects Kim saying that Scooby's eyes are bigger than his mouth. Scooby laughs and says "Scooby Dooby Doo."

A scrooge named Winslow Nickelby tries to close down a children's home so he can have it for himself. Meanwhile, a ghost is also haunting the children's home, just when Fred and the gang decorate for Christmas. Could these two things have any connection?

Professor Poisson, a world-renowned oceanographer, is on a quest assigned to him by the museum to go and retrieve artifacts from a sunken ship named the Diablo Doro. Along with him, is Mystery Inc.; Shaggy, Scooby, Daphne, Velma and Fred. They are boarded on a ship named the Sea Prowler. But the boat's operator, Mr. Carp, warns the professor and the gang that Diablo Doro is guarded by the ghost of Captain Pescado and his sea monster crew. The professor tells the kids these are just stories, and then informs the captain that they are over the Diablo Doro. They drop anchor and go to bed. That night, Scooby, Freddy and Shaggy see Captain Pescado's ghost, a kelp monster, and an octopus monster outside their window in the ocean. He informs the girls and they go on deck to check it out. There, they find wet footprints leading onto the boat. Suddenly, Captain Pescado appears as well as the Kelp Monster, appears and chases the gang. They run into Professor Poisson and warn him. Mr. Carp and the deck hands board a life boat and decide to row to port because of the ghosts. The next morning, the gang finds the professor's cabin ransacked, and Professor Poisson vanished. On the floor, is a secret code with the letter "IMCMMSC", their first clue. They decide to look for Professor Poisson. Scooby and Shaggy go into the galley and get locked inside by the octopus. Daphne, Velma and Fred get locked inside a room but manage to escape through a ventilation funnel. They look for Shag and Scoob, but get separated and Velma gets locked in the engine room. She climbs out through the smokestack where she is able to see the life boat that the captain and the deck hands got in. The gang reunites and discovers the life boat is empty and battered, covered in kelp and wet footprints. They split up, Velma, Shag and Scoob go to the radio room to try and send a distress signal, and Fred and Daphne try to find the professor. Velma, Shaggy and Scooby send part of a distress message using Morse Code, but in doing do, they alert the kelp monster and the octopus. The two aquatic goons chase all three of them. Fred and Daphne witness Captain Pescado diving back down to the wreck and then meet up with Scooby, Shaggy and Velma. Shaggy, Scooby, and Velma equip scuba suits and dive down to the Diablo Doro, and upon entrance, they discover air tanks, what does a ghost and sea monster need with scuba tanks? Scooby accidentally smashes through an old wall, and finds a treasure room-and the ghost and the sea monsters! Velma, Shaggy and Scooby are chased back up to the Sea Prowler. There they find the villains have gotten there first, and shoved Fred and Daphne into a closet. The ghosts then jump back into the water and they lift the submarine back into the hole, preventing the monsters from getting aboard. Velma explains that they must be taking the treasure from the wreck and hiding it on board. With the help of metal detectors, they find the treasure locked up in the brig, along with a bound Professor Poisson. They try to go radio for help, but Pescado, the Kelp Monster, and the octopus climb on board via ladder and chase Velma, Daphne and the professor and Fred, Shaggy and Scooby manage to trap Pescado and the sea goons in a net. The coast guard arrive in time to witness the outcome; the Ghost of Captain Pescado is unmasked as Mr. Carp, and the Kelp and the Octopus Monster are unmasked as the deck hands. The scribbled note "IMCMMSC" is wrong. The I is a 1, making it "1MCMMSC". "1MC" stands for First Mate Carp and "MM" means McFinn and McGil, the two deck hands. The "SC" meant Professor Poisson was trying to write scuba divers before he was attacked. Mr. Carp was trying to steal the treasure from the wreck and haul it back on board, the air tanks that Velma, Scooby and Shaggy saw prove that the alleged ghosts they had seen weren't ghosts at all. Scooby gets a laugh from wearing the treasures from the Diablo Doro, after Shaggy calls him the "six million dollar dog". To which Scooby responds by giggling.

The gang's headed to Decade Records to watch a live recording of a famous friend of theirs, Jimmy Lewis. Upon their arrival at the studio, they're greeted by an unwelcoming security guard named Joe. Then Jimmy lets the gang in, letting the guard know that they are friends of his. Jimmy tells the gang that one of his songwriters, Tony Synes, has disappeared, and left behind a strange piece of music that Jimmy tells the gang he'll be performing tonight. Jimmy introduces the gang to his pianist and arranger, Ian Barkin, Ace Decade, the studio owner's nephew, and the recording engineer, Brick Tyler. Ian begins to play the song written by Tony before he disappeared, but suddenly the recording equipment begins to malfunction. Then the gang hear about a phantom that's haunting the studio, much to Scooby and Shaggy's chagrin. Then Jimmy explains the phantom's the ghost of a musician seeking vengeance against those who ruined his career. Then Jimmy takes Fred, Daphne, and Velma on a tour of the studio, and then Shaggy and Scooby stay behind to play around with the equipment. Then the Phantom appears, who looks like a glam rock musician, and chases Shaggy and Scooby, stealing the piece of music that Tony Synes wrote before he went missing. Then Shaggy and Scooby find the gang and Jimmy and tell them of their encounter with the Phantom. Then Jimmy and the gang return to the studio to look for the Phantom, but he's gone, along with the music. Scooby and Shaggy go to Jimmy's dressing room to retrieve a copy of the music, and have another run-in with the Phantom, who tries to take the copy. Then the Phantom chases Shaggy and Scooby, going after the music, and Scooby and Shaggy manage to escape with the music. Then they meet up with the gang and tell them about the Phantom. Suddenly, the Phantom comes over the Intercom and threatens the gang. Then the gang decide to go search the offices for the phantom, and then Shaggy and Scooby go to the cafeteria to chow down. Then Velma, Fred, and Daphne find the source of the voice in Ace Decade's office, it was only a tape recording. Then Ace Decade tells the gang that he's got no idea how it got in there, and no one else has a key but himself. Then Scooby and Shaggy go to the cafeteria to eat, and then they think they've see the Phantom in a storage closet, locking him in. Then they run to tell the gang, but then they're caught and thrown out by Joe, the guard. Back in the studio, the recording session's cancelled and postponed until tomorrow. Then Scooby and Shaggy devise a way to get back into the studio, and in the process, find hundreds of Jimmy Lewis records in the trash cans outside. Meanwhile, Fred, Daphne, Velma, and Jimmy think of what could be so special about the song that Tony Synes wrote. Then Scooby and Shaggy get back inside and tell the gang about the clue in the trash cans, and then the Phantom appears and grabs the music, but the gang stops him and the Phantom chases them, trying to get the music, and in the process, gets tied up in reels of tape by Scooby. The Phantom is unmasked as Ace Decade. He was stealing records from his uncle's studio and selling them for his own personal profit. Shaggy now realizes that Ace was smuggling the records out in the trash cans. However, Daphne's confused, since Ace was the one who lead everyone to find the tape deck in his office. Fred tells Daphne that the tape recording in his office was a ploy to make it seem like he was being framed. The biggest clue was the song that Tony Synes wrote and left when he disappeared. The notes in the first three bars read ACEDECADE pointing an accusing finger straight at Ace. Once Ace heard the song, he realized what Tony did and faked the malfunction to stop the session. The Phantom was a cover for his operation to keep people away. Daphne wonders what happened to Tony Synes and Shaggy realizes where Tony is. Tony was the person Shaggy and Scooby locked in the storage closet because they thought he was the Phantom. Ironically, Tony thought Shaggy and Scooby were the Phantom. Scooby then tried to scare Shaggy, who held a mirror up and Scooby ended up scaring himself. He ran away and crashed into a drink machine, which poured a raspberry drink all over him.