When Fredburger was little, his "mommy" told him that babies grew on baby trees. He believed this for the rest of his life. When he was a little older, the evil bunny Bun Buns sawed off his extremely long tusks as seen in Underfist: Halloween Bash.
He has debuted in a episode of the show called Keeper of the Reaper, There, he is the protagonist of the episode. It is shown that he has his own home who uses his trunk instead of hands sometimes for object-verbs. It shows him eat a clothing hook and washing his teeth with his trunk. Until he reaches jury duty, the only thing he says is "Yes."
He has a strong desire for nachos, chicken, lollipops, frozen yogurt, chocolate-chip cookies, shrimps, and pizza. He is a former annoyance to a blue-monster who has a furious temper and a puppet-like accent, also to The Judge. He likes to spell his name: "F-R-E-D-F-R-E-D-B-U-R-G-E-R, Fred Fredburger! Yes!"
Fred was called for underworld jury duty in the case of the keeper of the reaper. The case was to decide which of the Grim Reaper's current owners would keep him once billy moved. Fred caused much chaos, angering everyone and disrupting constantly. He lost his home sometime after Mandy won the case, so he moved to the Pale Ghoulish Junior's home, or he forgot how to get to his own house.
Several months later, he had won the Poem Contest of a day with the Grim Reaper, where he was the only volunteer to enter in with 500 notes saying: I want to eet sum frozun yogert. He wasn't impressed of the Grim Reaper because he saw Mandy with "no nose" and also a lamp.
However, he was also taken to Sassy Cat Land written on the note by Mandy after Grim had upseted him into hiding in the Frozen Yogurt kitchen by knocking over his frozen yogurt cup accidentally when Grim was furious at Mandy's arrogance. At Sassy Cat Land, he flew away on the Ferris Wheel yelling out "FRED FREDBURGER!". His miserable future earned him a mention, that Fred Fredburger was HISTORY!! However, Fred survived the crash into Siberia or the Himalayas, where yetis had invited him for frozen yogurt and nachos, making him happy there forever.
Billy & Mandy's Big Boogey Adventure
He was one of the judge members in the case of stripping Grim of his powers. This was just like Keeper of the Reaper, except he didn't have to go to the bathroom at court. He accidentally read guilty as innocent on the declaration paper, corrected by the same blue monster from Keeper of the Reaper. Fred also was trying to eat and nibble on one of the hands. He also had made up a shrimp-buffet is in Boogeyman's ship, and only went on Boogeyman's adventure to go to the bathroom. He also paniced when Godzilla, King Ghidorah, Rodan, Anguirus, Gamera, and Gigan had fired flames on his bottom. Then, he became injured from a cannon-shot in acceptable loss by Mandroid, a robot built from the future. At the end, he had been shown to have been the one who took over the world and stole Horror's Hand from Grim's trunk at the main characters' house. Somehow, he gave back Horror's Hand because he probably gave up taking over the world or he was stopped by Grim.
Torturing Numbuh One
Mandy developed a television to carry Fred to weaken Numbuh 1 to reveal the secrets of Kids Next Door. Fred succeeded, and Numbuh One broke. Fred burst out with a rejoiced "Yes!"
Several months later, Fred Fredburger became one of the members in Underfist. He had made up the name himself with crayons and paint over the Underfist member truck's bedroom. He was redesigned with a more green color in texture and less fatter looking like a peanut. Fred also loves eating lollipops and used to like having caramel apples. He also volunteered to drive Hoss Delgado's Truck Stick. Then, he sang a song stageplay with Jeff the Spider that he doesn't want to grow up. He also defeated a mutant-cyclop chocolate bar with a Love-Lollipop and Hate-Lollipop by eating the lollipops.
- You killed my yogurt!
- F--R--E--D--F--R--E--D--B--U--R--GER: Fred Fredburger! Yes!
- Hey, uh, are you guys going to the Grand Canyon too on this cruiseship?
- Yes, my name is Fred Fredburger.
- My mommy said babies grow on baby trees.
- Frere Jacque, Frere Jacque, I gotta poo! I gotta poo! Flah-blah-blah-blah-blah-blah-, flah-blah-blah-blah-blah-blah-blah, Ding Dong for Fred Fred Burger! Yes!
- Have you ever been to jury duty before? This is my very first one. Gosh, I love paperwork, especially where I get to write my name.
- Judge, where are the nachos?
- I have to go pee pee!
- I have to make poo poo!
- Don't worry! I found some nachos!
- The nachos made my poo poo really stinky.'I enjoy shows about monkeys. I also enjoy shows about monkeys going to camp. I also enjoy shows about imaginary friends
- Can I come out of the TV now?
- Fred Fredburger's weaknesses, besides being incredibly stupid, include being put in televisions, cannonball shots and fire, and running out of nachos
- Fred Fredburger's friends include Blue Judge, Yeti Colony, Mandy, Billy and Jeff the Spider.
- As a child, his mother told him that babies came from baby trees, a "fact" that he believed for his entire life. ("Underfist: Halloween Bash").
- The rabbit Bunbun sawed off Fred Fredburger's tusks when he was sleeping, which were extremely huge, at some time, possibly when around early modern time. (Underfist: Hallwoeen Bash).
- When Fred Fredburger talks about liking tv shows he talks about a monkey going to camp(Camp Lazlo) and imaginary friends.(Fosters Home for Imaginary Friends)
- In the movie Underfist, Fred Fredburger is portrayed to be smaller than his original appearances, implying that the movie took place before his first debut, however this makes little sense considering that Dracula is shown living with Irwin's grandmama, an event that took place after Fred Fredburger's debut in Keeper of the Reaper.