A strange man who is the uncle and grandfather of everyone in the world must do battle with a gang of mutants, after an attempt to build a supercomputer to gain the appreciation and love of his favorite nephew goes awry.

• Note: Before the advent of the show of the same name, this same pilot was used as "the basis" for the 2011 TV series Secret Mountain Fort Awesome (i.e., the main characters of Secret Mountain Fort Awesome are based on the mutant characters in the pilot).

Uncle Grandpa shows up at a lame birthday party and tries to make it cool.

• Note: Was shown as the 16th episode of Secret Mountain Fort Awesome.

When a kid (voiced by Zachary Gordon) experiences difficulties with putting on his shirt due to his big belly getting in the way, Uncle Grandpa tries to make him feel better by going inside a Night Wolf shirt and teaching him about the benefits of having a big belly.

When Giant Realistic Flying Tiger fails to show up during a wizard battle, Uncle Grandpa and his friends follow her trail in order to find out where she went.

After accidentally sending Melvin (voiced by Jarid Root) who thinks he's a space emperor to an alternate dimension, Uncle Grandpa comes to the rescue.

• Special guest stars: Jarid Root as Melvin, and Tim Blaney as Emperor Krell.

Short: "Tiger Talk – Interview with Mr. Gus"

Only Mr. Gus can save the day when a funny face head Uncle Grandpa created takes on a life of its own and starts to wreak havoc in the RV.

Uncle Grandpa and friends are in a rush to get some emergency moustache cream.

Uncle Grandpa helps a kid called Eric earn his nickname with some intense yard work.

• Special guest star: Jarid Root as Spaghetti Legs.

Short: "Mr. Gus' Breakdance"

Uncle Grandpa helps Mary (voiced by Pamela Adlon) earn her drivers' license by showing her how to drive the RV.

Uncle Grandpa creates a duplicate of himself to babysit him while his friends go out for ice cream.

After Uncle Grandpa eats Dennis' diorama of the Pyramids of Egypt, he tries to make it up to him by bringing a real-life mummy to school.

After Uncle Grandpa and Belly Bag get stuck in peanut butter jars, it's up to Pizza Steve, and Mr. Gus to give a boy named Guillermo a new bike.

Uncle Grandpa and Belly Bag get locked out of the RV, and must get back so they, Mr. Gus, Pizza Steve, and GRFT can go on their mystery dates.

To avoid being laughed at, Mr. Gus tries to get his skin tight jean-shorts off before everyone sees him.

Uncle Grandpa and Pizza Steve control Adam's (voiced by Dee Bradley Baker) brain to help him become a video game master.

Uncle Grandpa and friends try to find a strange noise that's keeping them all awake.

Uncle Grandpa and his friends helps a dog named Charlie Burgers get his lost ball back.

Uncle Grandpa turns Austin (voiced by Carlos Alazraqui) into a robot so he can be perfect.

• Special guest star: Shaquille O'Neal as himself.

Short: "UG Rap Attack"

Uncle Grandpa and friends travel to Japan to help Akira (voiced by Jessika Van) make an action-packed monster movie.

Uncle Grandpa and Mr. Gus leg wrestle to decide what to watch on TV.

Future Uncle Grandpa arrives with a warning that stresses out Pizza Steve.

Uncle Grandpa hosts a blank episode for one lucky viewer (voiced by Jon Heder) to decide what the gang's next adventure will be.

When Uncle Grandpa gets out from the wrong side of his bed and says "bad morning" instead of "good morning", Mr. Gus, Pizza Steve, and Giant Realistic Flying Tiger attempt to lift Uncle Grandpa's spirits up.

Mr. Gus pulls a prank that leaves Pizza Steve in danger of being eaten.

Uncle Grandpa had sent a pair of pants back in time to 1492, but the pants were supposed to go to 1992, and Christopher Columbus won't give the pants back, and if Uncle Grandpa and Pizza Steve don't get the pants back by the end of the day, a guy from 1992 would call the time police on Uncle Grandpa.

• Special guest star: Ken Marino as Christopher Columbus

Short: "Shave Time"

After Uncle Grandpa misunderstood Pizza Steve when he was talking in the third person, he sends Pizza Steve to the moon (voiced by Tone Loc) so, Uncle Grandpa could be Pizza Steve's best friend.

Pizza Steve had set a goal to raise $13 million to get a jet he fantasized about, so he convinces Uncle Grandpa to start a food truck and sell burger dogs so Pizza Steve could have his jet.

The gang tries to show Uncle Grandpa that hide and seek is not an evil game, but things take a turn for the worse when Uncle Grandpa can't find his friends just like how he couldn't find his old friend Skeletony (Tony, voiced by Henry Rollins).

A documentary about one of the nuttiest wrestling matches to ever go down in history, showing how Chicken Man, The Best, and Mysterious Gus won all of their matches to make it the nuttiest wrestling match to ever happen in history.

• Special guest stars: Ric Flair as himself, and Jon Heder as Kev.

Short: "New Experiences with Beary Nice & Hot Dog Person – Imaginations"

After a failed attempt to give Uncle Grandpa his laser hammer, Uncle Grandpa must go inside of Belly Bag to see why he's not feeling well.

Uncle Grandpa is exhausted from helping all the time, and decides to go on vacation, only to find that being Uncle Grandpa is a full-time responsibility.

• * Special guest star: Tia Carrere as Island Girl

Short: "Tiger Talk – Cooking with Frankenstein"

Uncle Grandpa helps a teen named Riley (voiced by Scott Menville) go to a party only to realize that he has been grounded.

Uncle Grandpa uploads a video of himself walking on hot dogs onto the internet, and notices that someone didn't like the video. Mr. Gus tells Uncle Grandpa that the guy is just an Internet troll, but Uncle Grandpa suspects that the guy might be a real troll in disguise, and vows to slay the troll. Guest Star: Paul Rugg as Troll

Uncle Grandpa tries to make a girl named Jacqueline laugh at his jokes, but Jacqueline thinks that the jokes aren't funny, so when Uncle Grandpa sees what's going on in her body, he sees a bunch of monsters inside of her that are keeping her from laughing.

When Pizza Steve and Mr. Gus accidentally start to prank phone call on a intergalactic phone, they immediately get thrown in intergalactic jail and they must work together to escape.

Uncle Grandpa turns into a dog to teach a girl named Sandy how to be a responsible pet owner.

When Giant Realistic Flying Tiger chases a mouse (voiced by E.G. Daily) around the RV, Uncle Grandpa forces them to be friends but he has to face with the problem of the mouse destroying things in the RV along with Giant Realistic Flying Tiger.

• Special guest star: Piers Stubbs as English Muffinz

Short: "Lunch Break"

After Mr. Gus gets a hold on Pizza Steve's diary believing that it was Peter Pan, Pizza Steve tries his best to get the diary back before Mr. Gus starts to read about his secrets.

Uncle Grandpa has to go down to the City Court to pay for all of his parking violations but he crashes the RV into a basketball court next to the city court and is challenged by basketball players that want the RV.
Note: This episode was released in South America before in the United States.^{[citation needed]}

Tiny Miracle gets a low battery after the gang uses him too much.

Uncle Grandpa helps the new kid at school stand out on his first day, leading to (literally) hair-raising consequences.

Pizza Steve thinks Uncle Grandpa has been turned into a zombie, after watching a scary movie.

After being hatched out of his egg, Mr. Gus tries to convince Uncle Caveman not to feed him to the other hungry cavemen.

Uncle Grandpa receives a fortune from a fortune cookie and takes the fortune very seriously.

Uncle Grandpa gets too lazy and forgets to take the trash out, the trash overflows and Uncle Grandpa gets memory loss, when he wakes up he has to try to find his friends.

Mr. Gus becomes dumb after getting hit in the head by Pizza Steve.

Belly Bag decides to separate from Uncle Grandpa after a disagreement.

Andrew W.K. comes to host a party at the RV.

• Special guest star: Andrew W.K. as himself.

Short: "Dirtbag"

Uncle Grandpa had created an amusement park with rides featuring all the characters, and when Pizza Steve arrives at a roller coaster about him, he can't get on it because he's too small so he finds a way to sneak on.

Uncle Grandpa, Pizza Steve, and Mr. Gus follows a comet that's also taco to get a chance to eat it, but they must escape it from Area 51 when it lands on Earth.

Uncle Grandpa meets his number one fan.

Uncle Grandpa, Mr. Gus, Belly Bag and Pizza Steve go crazy trying to open a mysterious box.

Steve and Gus doesn't believe Uncle Grandpa when he claims a tree has begun talking because a criminal is inside of tree.

Uncle Grandpa turns a boy into a 300-year-old man, and must return him to normal.

This special episode is composed by three shorts, respectively directed by M. Wartella, Pendleton Ward, and Max Winston. They are:
1) "Time Burgers": Uncle Grandpa uses a time machine to sample famous hamburgers from the past.
2) "For Pete! Love, Pen": Uncle Grandpa and Pizza Steve hang out in a park.
3) "Total Reality": Uncle Grandpa is forced to entertain himself with his imagination after the TV breaks.

Pizza Steve makes up a preposterous lie to Uncle Grandpa in big trouble.

Uncle Grandpa helps Emily learn unconventional survival skills that help rescue her troop.

The gang must figure out a way to stop the RV's talking computer system when it malfunctions.

• Special guest star: "Weird Al" Yankovic as Weird Pal^[66]

Short: "New Experiences with Beary Nice & Hot Dog Person – Bath Time"

Mr. Gus tries to watch a movie peacefully but Pizza Steve and Uncle Grandpa keep causing a ruckus.

Belly Bag befriends a fellow bag who turns out to have sinister intentions.

• Special guest star: Tommy Chong as Bottom Bag

Short: "Cloud Gazing"

Uncle Grandpa tells how he became a laughing stock when he got an entire watermelon stuck in his mouth.

Birdman makes a new home in the RV's attic.

• Special guest star: Jonah Ray as Birdman

Short: "Duck-tor Appointment"

Uncle Grandpa fills in for the RV's spare tire and enjoys it so much he decides to remain a tire forever.
Note: In this episode, Dick Dastardly and Muttley (from Wacky Races) make a cameo.

Belly Bag turns into a werewolf on the night of a full moon after Uncle Grandpa installs a moon roof on the RV.

Uncle Grandpa and his friends go to the mall to buy a secret santa gift, and end up racing for one of the hottest new toys.

• Special guest star: Keith David as Mall Santa

Pizza Steve's dad Nacho Cheese visits and gets on everyone's nerves.

• Special guest star: Henry Winkler as Nacho Cheese.

Uncle Grandpa travels to the Mustache Tree to stock up.

Uncle Grandpa has to travel back in time to return a library book.

When the Easter Bunny is unable to fulfill his duties, Uncle Grandpa steps in to help with egg-delivery.

• Special guest stars: Regis Philbin as the Easter Bunny

Short: "Slice of Life with Pizza Steve – Mutant Pizza"

Things get out of hand when Mr. Gus fulfills a timeless legend and is deemed king of the food court.

Short: "Beastoid Bros"

• Special guest stars: Richard Christy and Sal Governale as the Beastoid Bros

The gang attends the premiere of Majestico and Uncle Grandpa Boy, a movie about a little girl who wants to be a super hero.

Pizza Steve tries desperately to make the others in the RV interested in his new game console.

In the year 3021, the gang's intergalactic mission goes awry when a strange alien creature infiltrates their ship.

When pieces of their shadows are stolen by a shadow demon, Uncle Grandpa and the gang must travel to the Land of Lost Shadows in order to retrieve them.

• Special guest star: MC Hammer as himself

Short: "Waiting for Coffee"

Uncle Grandpa falls for Pizza Steve's "girlfriend" and ends up in serious danger.

Short: "Grampies"
Note: Characters from several Cartoon Network shows appear in this short.

• Special guest stars: Natalie Palamides as Buttercup, John DiMaggio as Jake the Dog, Zach Callison as Steven Universe, Roger Craig Smith as Belson Noles

Uncle Grandpa's gang joins Aunt Grandma in helping children after seeing a hate video of them.

• Special guest star: Mark Hamill as Joss Bossman

Seth must clean his room and learn to be a neater person in order to keep Messy Bessy from making his life a nightmare.

The gang helps Charlie Burgers get rid of his fleas.

When Pizza Steve borrows Uncle Grandpa's sunglasses, he sees things in a whole new light.

In order to rescue Uncle Grandpa and the others from a gang of evil vegetables, a young boy must learn to eat his food.

Uncle Grandpa helps a boy get his head out of the clouds and focused on his history test.

In Argentina, Uncle Grandpa turns Thiago into a fly to overcome its fear of flying.
Note: This episode was released first in Latin America on May 8, 2016.

In Australia, Uncle Grandpa helps a kangaroo collector to be giving a zipper on the stomach as his bag. But this animal is obsessed with collecting all Australia, which was warning of "other Uncle Grandpas".
Note: This episode was released first in Latin America on May 13, 2016.

In France, Uncle Grandpa helps a child that others have good taste of its models clothes, ending up as slaves of an alien.
Note: This episode was released first in Latin America on May 8, 2016.

In Italy, Uncle Grandpa brings the future to Leonardo da Vinci to be the Mentor Inventor of a girl. But this mentor is not satisfied with the future.
Note: This episode was released first in Latin America on May 8, 2016.

Uncle Grandpa tries to meet Pizza Steve's imaginary friend by turning himself back into a baby.

A Dinosaur Day celebration is ruined by Pizza Steve's jealousy.

Mr. Gus and Pizza Steve compete in the RV Olympics.

Note: This episode celebrates the Rio 2016 Olympic Games.

A rock band joins Uncle Grandpa to help a young girl win a talent show.
Note: This episode was originally going to be called "Ambient Hostile Takeover", a play on the Melvins album Hostile Ambient Takeover.

• Special guest stars: Buzz Osborne and Dale Crover as themselves.

Short: "Rock 'n' Roll Check-up"

When a Little League team needs help, Uncle Grandpa enlists a few famous baseball players to help.

• Special guest stars: Adam Jones, Chris Archer, David Price, José Altuve, and Noah Syndergaard as themselves.

Short: "Tiger Talk - How to Make a Breakfast"

Uncle Grandpa makes improvements to a kid's Halloween costume by turning him into a real candy bar, but things get out of hand when other kids try to eat him.

Uncle Grandpa takes a kid to the North Pole to experience an epic snowball fight.

Pizza Steve keeps a secret from the gang.

Uncle Grandpa cures hiccups for a kid.

Uncle Grandpa and a kid embark on a dangerous jungle adventure in search of a legendary MacGuffin.

Uncle Grandpa's new found confidence makes his head big.

Uncle Grandpa grows a ponytail which gains him the attention of a magical pony.

Uncle Grandpa and Mr. Gus must rescue Pizza Steve from the Tooth Fairy.

Uncle Grandpa's present for Mr. Gus gets loose and causes trouble.

Uncle Grandpa turns Tiny Miracle into a robot version of himself to help with his duties.

Mr. Gus's nephew terrorizes Uncle Grandpa and Pizza Steve.

Uncle Grandpa helps a young wannabe magician by teaching her a new trick.

Uncle Grandpa helps a shy kid gain confidence.

• Special guest stars: Maile Flanagan as Ricky and Justin Roiland as the Tongue

Short: "Ule Gapa's Collection"

Uncle Grandpa and Pizza Steve try to convince Mr. Gus that his ventriloquist dummy is alive.

Uncle Grandpa and Pizza Steve help Mr. Gus try to get his face back to normal before an important photo shoot.

A threatening phone call from a stranger causes the gang to panic.

Uncle Grandpa gives a lovesick Cupid some dating advice.

• Special guest star: Greg Proops as Cupid

Short: "New Experiences with Beary Nice & Hot Dog Person – Restaurant"

Uncle Grandpa gets a vaccine at the doctor's office.

Uncle Grandpa and Mr. Gus accidentally eat Pizza Steve's birthday cake for his mom and must try not to tell him.

Uncle Grandpa helps a girl fall asleep by counting sheep, but one goes missing.

Uncle Grandpa helps out a stinky cat who's down on his luck.

Uncle Grandpa and the gang must retrieve Tiger from the pound before she's adopted out in a musical-style episode.

• Special guest stars: Tyler the Creator as the Construction Manager, Bill Moseley as Quirky Salesman, Arlene and Angel Deradoorian as the Hair Mermaids, and Justin Pearson as Free Sample Elf

Mr. Gus and Belly Bag are throwing a surprise party for Pizza Steve, as long as Uncle Grandpa doesn't spoil their surprise.

Uncle Grandpa hosts a talk show featuring bands such as Mr. Gus and the Jurassic Jam, Giant Realistic Flying Rock Band and an appearance by Pizza Steve and a talking baloney sandwich.

• Special guest star: Marky Ramone as himself.

Uncle Grandpa enlists a famous film director to help a kid improve his film acting skills.

• Special guest star: Robert Rodriguez as himself.

Short: "Inside the Director's Mind with Uncle Grandpa"

Uncle Grandpa digs a hole, with the other Uncle Grandpa's down there in the hole, they hang out and plot to take down The Overlord.

When the Boogie Man loses his mojo, Uncle Grandpa steps in to help.

• Special guest star: Robert Englund as the Boogie Man.

Short: "Uncle Gretel and Pizza Hansel"

Trying to enjoy dinner, Uncle Grandpa and the gang keep mysteriously being sent back and forth through time; they realize it's film transitioning and they find out the editor was sleeping & they wake him up. And, they put a stop to the transitioning.

Uncle Grandpa visits the cartoon factory to get some answers about his roots. (Pete Browngardt stars as a cartoon version of himself.)

Pizza Steve and Mr. Gus try to help Uncle Grandpa get an idea.

Uncle Grandpa makes it hard for Pizza Steve to prove he's not a baby.

• Special guest stars: Anders Holm as Deep Dish Dave and Blake Anderson as Ciabatta.

Short: "Guess the Character"

Similar to the others shorts episodes (particularly "Guest Directed Shorts"), this episode is composed of four shorts.
1) "Late Night, Black Light": After the lightbulb in the UG RV living room breaks, Uncle Grandpa plugs in a fluorescent lightbulb, and things get pretty crazy.
2) "I Love My Friends": Uncle Grandpa accidentally breaks a tire that a homeless cat was living in and the gang discuss what to do with him.
3) "Uncle Grandpa vs Mr. Gus": In this Batman vs. Superman spoof, Mr. Gus is ordered by the President to destroy Uncle Grandpa for being too funny, and an epic battle ensues.
4) "Good Morning": Uncle Grandpa says his signature catchphrase to everyone in the world.

Uncle Grandpa helps Samir overcome his paralyzing fear of the high dive.

Pizza Steve goes to great lengths in order to beat Mr. Gus at a game of chess.

Upon seeing the gang have a fun time swimming and eating ice cream, Tiny Miracle realizes he wants to be a real boy.

Uncle Grandpa is in need of some extra cash, so he starts charging for his services.