He first made an appearance in Timmy in Space where he tells Timmy that they've taken over control on the new space station on the Planet Shmengee. When Timmy first meets Sidney Cyclops on the planet Shmengee, the Goon makes an announcement to welcome to "his" planet. Back in the space station, the Goon and Ms. Sweety tell what they have planned for Timmy. When Timmy and Sidney were doing the Ice-Cream-Man Plan, when Sweety goes ga-ga over ice cream, the Goon tells her to snap out of it by having her lick a lollypop. He congratulates Timmy for failing the Ice-Cream-Man Plan, and finishes the lollypop. When Timmy, Brushbrush, and Sidney were doing the Sugar-World Plan, the Cavity Goon realizes that they're playing Sugar-World. It is revealed that Sugar-World is his favorite game in the whole galaxy, because he is the most intergalactic Sugar-World champion. He decides to play one teensy-weensie game, and then he'll win. But Sweety warns the Goon to not play the game, because it is a trap to get them out and have the good guys take back the space station. The Goon tells them that nobody plays Sugar-World anymore. After Bubbles Gum tells Timmy that he needs Plan B: A Bigger Better Bolder Plan, the Goon reminds Timmy he needs to do more than Plan B, and what he needs is Plan C: Cookies, Candy, and Cupcakes. Later, the Goon tells Sweety to dump the trash out for Timmy, Brushbrush, and Sidney's plan to fail, until Timmy, Brushbrush, and Sidney show up as they have to swap characters in the two different places. They got it mixed up three times (one of them is having all the characters outside the space ship), until the Goon and Sweety are out of the space station for good, and for this punishment, they have to clean up the mess they have made by cleaning up the garbage, and during that time, the Goon tells Sweety to jump down but Sweety refuses, but she does it anyways. The Goon lies about Sweety to be jumping down
In Operation: Secret Birthday Surprise, when Sweety wakes up the Goon, he wakes up as he notices that it is absolutely not an icky day because the sun is shining, the birds are singing, and butterflies are flying all around him. He cries about it until Sweety reminds him its a "beautiful-terrible" for them to stick some chewing gum under the swing sets in the park. Later in the dream-sequence, when Timmy sees how Brushbrush is really doing without him, he notices that the Cavity Goon is living in his house. The Goon tells Brushbrush to make his morning candy and make it sweet. He later sings a song about how yucky and icky he is which is the closest thing to have in a Muppet villain song. After that, Brushbrush comes in with the Goon's morning candy, and then the Goon tells Brushbrush that he needs to mess up the kitchen, and the living room, and the basement, and not do the laundry, and that when Brushbrush is done with that, the Goon wants Brushbrush to take out the trash and dump it in the driveway.
In Malibu Timmy, during the second heat of The Guys and Girls Who Can Swim Surfing Contest, Big Dan the Surfing Man interviews the Cavity Goon (in which he and Bob refer to him as "Goondoggie") on how he plans to win the surfing contest. The Goon plans on cheating, in which Dan finds it not very fair, but to the Goon, that's the idea. The Goon sings a song about how he cheats. After the song, the Goon reminds Dan one more thing that he's going to win, but Dan asks him if he could surf, but the Goon doesn't even swim, but he takes over the microphone from Dan and says that he's going to win anyway. Later during Johnny Paste's surfing, the Goon was seen surfing with an anchor as a little present for him as he tosses the anchor at Paste, but Paste declines as it misses Paste. The Goon was being pulled by the anchor instead of having the anchor hitting Paste, which makes Paste safe. Soon when they asked where Goondoggie is, they found out that he is drowning. Later, Timmy the Tooth (as lifeguard Malibu Timmy) is reminded that he needs to save somebody as Gil the Grouper suggested, he saves the Goon from drowning. It is revealed that he hates saltwater (except for saltwater taffy that is). He tells Timmy to unhand him, but Timmy tells the Goon to save him whether he wants him to or not. The Goon just lets go of Timmy and then gets sunk into the bottom of the ocean.
He and Sweety had a big part in Lost My Brush where they try to kidnap Timmy (and Brushbrush to lure him) in an attempt to turn him over to the Tooth Fairy for money. In the beginning of the episode, he and Sweety discover Timmy the Tooth's house and plot on how they can get rid of Timmy by explaining how icky sticky and nasty he is until he founds out that they're being watched and tells the camera to go away, because they do need their privacy, but the camera turns back on them in which the Goon tells the viewer that they never heard of privacy and he and Sweety tell them to go away again. Later, they disguise themselves as The Flossmore Brushman and Ms. Stripe to get Timmy's attention on getting a new brush by telling that Brushbrush is used up, old, tattered, bedraggled, bothered, and bewildered. The two bad guys highly recommend the Brush-O-Matic. Timmy wasn't interested in it and tells the two to go away. The Goon also recommends some paper towels. Timmy was still not interested anyways. When Timmy and Brushbrush fall asleep, Timmy dreams that the Goon tells him that its time to get a new brush and get rid of the old one. The Goon and Sweety are trying to keep an eye out on Brushbrush in order for them to get rid of Brushbrush so they can capture Timmy the Tooth, and when they captured both of them, they'll have all the Tooth Fairy loot they'll have. They sing a song about being rich and how they can be cashing in. After they finish their song, they're really ready to get rid of Timmy and Brushbrush, that is until Annette Bruner Prower comes along and notices the Flossmore Brushman. She tells the bad guys what happened to her brush when the Goon notices that its time for them to go. The Goon and Sweety need a bigger plan to get rid of Timmy and Brushbrush, so they get rid of their costumes and dress up as dog-catchers and capture Brushbrush with a net. They find a way to keep Brushbrush. Sweety suggests the Lost-and-Found, because Brushbrush was lost when he was chasing butterflies and found when he was caught. The Goon and Sweety take over Timmy's house for real and got rid of Timmy's couch when Timmy found out what happened at his house when he heard something going on in his house. This leads to a chase scene where Timmy gets real mad and starts to chase Sweety, but how is Sweety supposed to run in her heals? When Timmy was still chasing Sweety around, the Goon pops up and captures Timmy, until the door slams open and hits the Cavity Goon and reveals Brushbrush, Bubbles, and Sherry the Fairy. The Goon is ready to give up when he tells Timmy to call off his brush, but Timmy tells the Goon not to do so until the Goon leaves. The Goon asks about his money so he can get rid of Timmy the Tooth. Sherry tells the Goon that everyone knows the Tooth Fairy comes only if its your tooth. Which means that Timmy the Tooth can't be replaced. The Goon and Sweety surrender and leave at once.
The Goon and Sweety have to play different roles other than themselves in The Brush in the Stone. The Cavity Goon has to play a Fire-Breathing Shadow Dragon, in which he uses a paper stick puppet dragon and not being one. When Squire Timmy and Bubbles Hood wander through the Not-So-Sure-Its-A Forest where they encounter the polka berries when they saw a shadow of a fire breathing dragon who is about to eat them which is actually the Cavity Goon and Ms. Sweety are controlling a small paper dragon with the Goon holding the miniature dragon and Sweety holding the lantern. When Little Brush see the two puppeteers, he begins to attack the Goon which results into a chase scene for the Goon and Sweety to stop the brush. The main reason why the Goon and Sweety are in charge of this part of the forest is because they have keep charge of the polka berries so they can have them all to themselves. Timmy decided to trade something with the Cavity Goon and Sweety so the good guys can have the berries. He traded his puppets for the berries for the Goon and Sweety so they can perform puppet shows for The Gingivitis Gang.
In Rainy Day Adventure, the Cavity Goon and Ms. Sweety play as pirates as they capture Sunny the Sun in order to make it dark and cloudy so everyone everywhere will be as miserable like the Goon himself. The two sing a song about how they like it dark and cloudy and not sunny and bright. When the Goon and Sweety see Captain Goodguy (played by Timmy the Tooth)' and First Mate Brushbrush, this results in a chase scene from the water to the atmosphere to the desert to Big Mouth Gulch (location) where it was so dried up that when Captain Goon and Sweety stopped by at the lemonade stand, Bartender Paste informed them that all the lemonade has turned into sand. When the Goon and Sweety left the bar, the found out that Sunny has been stolen from them to Cowboy Goodguy, so the chase resumed back into the air, but when Timmy and Brushbrush's boat accidentally tipped it made Sunny fall down into an ocean near Hawaii which made the Goon and Sweety find out that their job has been done for them. When Sunny comes back to the sky, the Goon decide to go to the Cave of Crud where they'll think of something icky to do there.
In Big Mouth Gulch, once again, the Goon and Sweety have to do roles other than themselves. The Goon plays as the role of Goony the Kid (otherwise known as Sloppy McDemot, Nasty McSlime, and most of all, Goonius Nemesis the Third). Goony was first seen in the episode walking into the lemonade bar when he realizes that there's no one here until Gil (the bartender) expects someone else. The Goon asks Gil to give him a glass of their finest lemonade and he says meanly to Gil to make it snappy. He must've forgot his manners. So he says his request again in a much nicer way. Gil gives him a glass of lemonade and asks him who he is. The Goon gives out his card to Gil as it reads Goonius Nemesis the Third. Sheriff Timmy meets Goonius and Goonius tells Timmy that he has changed his ways, clothes, and his socks. He cleaned up his act and he's no longer the mean messy goon that he was. Timmy asks Goony what he's here for. Goony tells Timmy that he's merely seeking employment and he wants the Sheriff's job! Goony tries to proof the citizens of Big Mouth Gulch that's he's the better sheriff by telling them that Timmy once returned a book to the library late, often having in between meal snacks, and not washing behind his ears. If the townspeople of Big Mouth would rather consider Goony as the new sheriff, there will be honesty, fun, and plenty of free lemonade. Ms. Page Turner (played by Bubbles) proves to the townsfolk that he's really Goony the Kid. Goony tells Sweety to steal the necklace of Anita (played by Annette) and place it under the sheriff, in which Sweety did to prove that Timmy's a thief. Goony suggests that he and Timmy will have a showdown at 12:00 noon, but Timmy can't do it because he has to pick up some brand new cowboy boots, which would make the showdown start at 12:05 instead. The showdown begins as usual until Timmy asks Goony about Timmy's new cowboy boots. The Goon compliments on those boots until he realizes that they have a showdown to do. Timmy shows Goony how showdowns are settled in Big Mouth Gulch, in which it results in Ms. Flossy and the other Big Mouth Gulch patrons singing "Let's Have a Spelling Bee". The spelling bee begins as Mayor Paste explains that the winner of the spelling bee will become sheriff forever. So the spelling bee begins with Goony spelling the word "Cat" in which the Goon spells it incorrectly as "Kat", but Timmy spells it correctly and explains the definition of the word out to the crowd. The next word is "Book" in which the Goon incorrectly spells again and gives out the wrong definition, Timmy gives out the right spelling and definition of the word again The final word of the spelling bee is "Aluminum" in which the Goon and Sweety try to find the word in the dictionary couldn't find it because Ms. Flossy told them that there's no help aloud in the spelling bee. Timmy proves to the Goon and Sweety that there is such word as aluminum by spelling it out for them. The Goon loses and Sheriff Timmy wins the Spelling Bee and becomes Sheriff forever!
- Timmy in Space
- Operation: Secret Birthday Surprise
- Malibu Timmy
- Lost My Brush
- The Brush in the Stone
- Rainy Day Adventure
- Big Mouth Gulch
Muppet Treasure Island (he was seen at two Benbow Inn scenes: in one scene he was a Benbow customer, and in another, he was seen as one of the pirates attacking the Benbow Inn)
- Muppets Tonight
- Episode 104: John Goodman
- Episode 105: Cindy Crawford
- Episode 108: Jason Alexander (performed by Brian Henson)
- Episode 109: Whoopi Goldberg