Uncle Grandpa is the pilot episode of the series. It was an episode of "The Cartoonstitute," and also served as a pilot for "Secret Mountain Fort Awesome".
Uncle Grandpa accidentally destroys Ham Sandwich's computer, then tries to make a supercomputer for him, but makes a mutant maker by mistake.
The episode starts off with a man walking outside to pick up his newspaper. Within a few seconds, he stops and puts his hands on his ears as a screeching sound is heard in the background. He begins to scream for a few seconds before Uncle Grandpa's RV drives past him swiftly.
Uncle Grandpa is shown in his bed wide awake. He continues to greet the audience with a "Good Morning" as he gets up and begins to walk around. He switches his head from one body to another body that is fully clothed as he walks up to a mirror. He waves to his reflection and tells it "Good Morning". The reflection spins his hat and repeats "Good Morning" in response. Uncle Grandpa flies over the mirror and lands through Belly Bag. When he gets up, he adjusts Belly Bag and sings "Good Morning". He then walks on and receives a giant mug filled with coffee that says "World's Best Uncle and Grandpa" as he says "Good Morning" yet again. He then dumps the coffee on himself and makes his way over to the cockpit, wondering what he has in store for himself today. As he reaches the cockpit, he realizes no one is driving the RV. Upon realization, the RV crashes into a house.
This crash sends Uncle Grandpa sailing through a kitchen with a mother and a father sitting at the table. He greets them with a "Good Morning", but they don't seem too enthusiastic to see him. Uncle Grandpa then goes flying through the living room where the kids are. He greets them with a "Good Morning" and they seem excited to see him. He tells them to stay in school and not do drugs as he makes his way up the chimney and into the sky. There he lands on a plane where he frightens a few pilots while greeting them with a "Good Morning". After a few seconds, they seem unenthusiastic as they realize who Uncle Grandpa is. Uncle Grandpa then falls off the plane and lands in Ham Sandwich's room.
While Uncle Grandpa lands, he accidentally breaks Ham Sandwich's computer. Ham Sandwich is completely devastated over this broken computer and questions who Uncle Grandpa is. When Uncle Grandpa explains who he is, Ham Sandwich immediately calls for his mother, Judy Jones. Judy Jones comes into his room and is excited to see Uncle Grandpa there. She further explains who Uncle Grandpa is to Ham Sandwich. Ham Sandwich seems to not care about the family talk and points out that Uncle Grandpa destroyed his computer. Judy tells her son that Uncle Grandpa didn't mean to do it. Uncle Grandpa then offers to build Ham Sandwich a new computer that's better than his other one. Ham Sandwich seems pretty pleased with this promise and follows Uncle Grandpa into the backyard.
Ham Sandwich stands there with his eyes closed as Uncle Grandpa builds his super computer. After a little bit of building, Uncle Grandpa reveals Ham Sandwich's new super computer. Much to Ham Sandwich's disdain, the super computer is not a super computer at all. It's actually just a toilet with a large pile of garbage on top of it. Ham Sandwich announces he is leaving to go to his room in a very childish tone and also reveals that he hates Uncle Grandpa. Ham Sandwich slams the door behind him and leaves Uncle Grandpa outside with the toilet.
Uncle Grandpa decides to see what his new creation can do by pulling down the toilet's flush lever. The toilet blows up and sends Uncle Grandpa flying into the fence. As soon as the explosion ends, a disgustoid that looks alot like Festro comes out of the toilet and begins to speak in some strange language. Soon, a bunch of other monsters (most likely Disgustoids) begin to pile out of the toilet and start running amok around the backyard.
Meanwhile, Ham Sandwich is sitting in his room sulking over his broken computer. He suddenly hears a knock on his window, and immediately becomes frustrated. He believes the knock is from Uncle Grandpa, who he is thoroughly annoyed with. Ham Sandwich tells Uncle Grandpa to leave him alone as he opens the window's curtain. Instead of seeing Uncle Grandpa, he actually sees a Disgustoid. Ham Sandwich panics and runs out of his room, where he meets other Disgustoids in his hall. Ham Sandwich screams as he runs down the hall way, but is immediately silenced by Uncle Grandpa who drags him out of the hallway and quickly into a nearby closet.
Uncle Grandpa explains to Ham Sandwich that the "super computer" he created was actually a mutant making machine. He then suggests that they need to do something or they will destroy the house. Uncle Grandpa goes over the plans to Ham Sandwich as he views a young Tony Danza poster. Ham Sandwich panics again. Uncle Grandpa tells him to relax as he opens a portal-like door on the ground and enters it, dragging Ham Sandwich along with him. They end up going into the RV where Ham admires Uncle Grandpa's items and Uncle Grandpa retrieves weapons from a chest. Uncle Grandpa chooses a mallet and Ham Sandwich chooses a barbarian sword. Uncle Grandpa hops onto Giant Realistic Flying Tiger, which greatly surprised Ham Sandwich. They ride Giant Realistic Flying Tiger into Ham's house and immediately begin an epic battle with the Disgustoids. They destroy some of them and the rest of them flee to the toilet. Uncle Grandpa sits on the toilet and acts like he's going to go to the bathroom, causing the toilet to blow up. Ham Sandwich celebrates their victory, but is surprised to see Uncle Grandpa not there. He tells Judy everything that happened between him and Uncle Grandpa. Judy passes it off as a silly story and also explains to him that Uncle Grandpa has a habit of disappearing after bringing you on an adventure. Ham is bummed out by this and glumly walks into his house. Judy offers to buy him a new computer, but in response she hears a scream coming from Ham's room. When she goes to check on him, she sees Ham sitting on top of Giant Realistic Flying Tiger. He claims that he doesn't need the computer when he has Giant Realistic Flying Tiger. It then shows Uncle Grandpa in his bed in the RV saying "Good Morning" again before the pilot ends.
- The first monster that comes out of the toilet become Festro in Secret Mountain Fort Awesome. On a secondary note, the third monster slain by Uncle Grandpa would become Dingle, also in "Secret Mountain Fort Awesome".
- Belly Bag is an inanimate object in this episode.
- The pilot shows the trademark "MAD Magazine" style which Peter Browngardt is now known for.
- The excessive detail and scratchy line-work would be displayed in "Secret Mountain Fort Awesome" and to a lesser extent, the series "Uncle Grandpa".
- This pilot is the core of the show that would later be repeated in the series. Pizza Steve and Mr. Gus do not exist yet, Belly Bag is not alive, and Giant Realistic Flying Tiger is the same, but Uncle Grandpa gives her to Ham Sandwich.
- Uncle Grandpa's design was different here. He has layers of wrinkles over his eyes, he has bags (under his eyes), his chin's detail is in an "X" shape, and his legs are hairy.