Costume Crisis is the sixth episode of Uncle Grandpa Season 4, and the eleventh episode overall of the series. It is the fourth Halloween episode of the series.
Uncle Grandpa is sleeping until the moon rises and he rises dressed as a vampire and is happy that it is Halloween night and he flies off. Uncle Grandpa is going through the gang's costumes as well as his costumes, he stops when he gets to Pizza Steve and he wonders why he does not have a costume, Uncle Grandpa explains to Pizza Steve that everyone dressed for the occasion and that in this country first you get the idea, then you get the costume, and then you get the candy. Pizza Steve claims that he is dressed and he reveals that he is wearing a pizza Steve costume and everyone is amazed. The door begins knocking and everyone freaks out at the first trick-or-treater, Uncle Grandpa wants to make sure that everything is perfect, he opens the door and everyone is blinded by the terrifying costume they are witnessing. The light dies down and it shows a child wearing a shirt that says "Costume" and asks for candy, everyone gets disappointed and Uncle Grandpa gets mad that it's not even a costume, Chet says that it is a costume since it says it and he thought it was a good idea, Uncle Grandpa begins to yell at him saying that it's the most unoriginal, uncreative, unfunny costume ever. He explains that Halloween is sacred and it's an opportunity to escape their mundane lives, an opportunity to be something interesting for just a night, Halloween is not just about candy and it is something bigger than that and it is about being something you're not. Uncle grandpa tells Chet not to worry as him and his pals can help him with his costume crisis, everyone left to go trick or treating, Chet tells Uncle Grandpa that he wants candy and wonders if he will get any this Halloween, Uncle Grandpa has got just the thing for him though. Uncle Grandpa shows Chet the custom costume creator generator and guarantees Chet that he will impress everyone with his costume and shoves him the machine, Uncle Grandpa transforms Chet into various costumes to find the right one.
Uncle Grandpa asks Chet what he likes and he replies with candy, Uncle Grandpa then transforms Chet into a candy person and he loves it, Uncle Grandpa is happy to see Chet in the spirit and he gives him an empty pillow case to hold all the candy he is going to get from his awesome costume. He pushes Chet out the window in the back and tells him to have fun and get a lot of candy, and that he will change him back when he's ready. Chet thanks him and he goes off. Uncle Grandpa dressed as Finn from Adventure Time opens the RV door and says, "IT'S CANDY TIME!" and proceeds to throw candy to the children.
Chet is walking down the street wondering what kind of candy he will get first, two children walking down the same street sees Chet and one of them suggest to eat Chet and they both agree on it chase after Chet, the two children following him vow to look for Chet and eat him, Chet wonders how if children want to eat him then how will he eat any candy. A child dressed as a bush grabs hold of Chet and he runs away, he hides behind a house and figures that the candy costume was not a good idea. Uncle Grandpa pops out from a window and thinks it's a cool idea, Chet is glad to see Uncle Grandpa and he tells him his dilemma about kids wanting to eat him and asks him to change him back. Uncle Grandpa tells Chet to lean in until it is revealed to be a girl dressed as Uncle Grandpa, Chet sees it and runs away.
Chet runs up to a police officer telling him he has to help him, the police officer tells Chet that the safety of trick-or-treaters is his number one priority tonight, he then places a ticket on a car windshield. Chet asks the cop if he is not a child that wants to eat him, the cop says that he is not a child, rips off the costume and says he is two children and Chet runs again.
Chet runs to the RV and bangs on the window begging for Uncle Grandpa to change him back, Uncle Grandpa states that he's in a bit of a pickle, he ran out of candy and he is handing out costumes and as soon as he is done he will change him back. A dog starts to chase Chet and questions that if dogs aren't supposed to eat chocolate, the dog is revealed to be a child and wants to eat Chet. Chet runs into a school and places a "no dogs allowed" sign on the door. A judge for the costume contest sees Chet and tells him to hurry, Chet thinks it'll be fun and wants to know if there is s a prize, the judge says that Chet is the prize and Chet really wants Uncle Grandpa.
Uncle Grandpa gives away the custom costume creator generator and he can't believe that he ran out of candy and costumes. Uncle Grandpa figures that he should go get something to wear to find Chet, he looks in the RV and everything is gone except for Chet's costume shirt.
At the costume contest, there are three children to be chosen for the finalist and only one gets to eat the giant candy bar grand prize and before the judge can make the final decision, Uncle Grandpa walks in and wonders if that is Chet on stage and wonders why he is tied to a board. Chet wants Uncle Grandpa to change him back, the judge sees the shirt Uncle Grandpa wearing and thinks it to be the most original, creative, funniest costume he has ever seen and tells Uncle Grandpa that he won the grand prize, everyone else is jealous of Uncle Grandpa. Uncle Grandpa tells Chet that he was wrong about his original costume and sorry that he put him through that and that he can change him back. Chet thinks it is cool but he still did not get any candy, Uncle Grandpa takes a chunk of Chet and presents it to him and says, "Happy Halloween!"