Abandoning his dream of becoming a Jokester, Tylor sets his sights on becoming the perfect MIFTer. But when he loses the sacred hair of David, a former employee, Tylor must get it back before the MIFT team finds out.
Tylor has finally decided to give up being a Jokester and instead be the perfect MIFTer. He arrives with donuts, but the rest of MIFT incinerate it as it is David Day, the day they celebrate former MIFTer David who had died after getting pulled into a shredder shaft (David did not like donuts). MIFT acts as if he is still around and keep a lock of his fur as a tribute to him. As they pretend to get haircuts, Tylor decides to go and perform their duties while they wait so that they can see that he is just as good as David was.
Meanwhile, Tylor tries to feed Roto, but he escapes his container and eats David's hair before getting sucked up in one of the tubes. Tylor panics and desperately tries to get a lock of Roze's hair as it looks similar to David's. He fails when she finds out what he is up to and runs into Val who takes him to have David's lunch. The crew tell Tylor about what had become of David and where the shredder shaft is. As he rushes over there, he accidentally activates it and knocks himself out with his helmet as he tries to escape.
In a near death experience, Tylor is visited by the spirit of David, who only seems to speak in generic philosophical phrases, before finally giving him a lock of his hair. Tylor asks what he needs to do to be a good MIFTer, to which David tells him, "Be reliable and honest... and don't eat barfalo wings. They can give you a number six." Tylor awakens to see that he is holding Roto and takes him back. He is visited by Roze who has decided to give him a lock of her hair as he reminds her of herself, though she neglects to tell him where exactly the hair came from, disturbing him.
MIFT holds a candle vigil for David to finish up the day, but everyone begins to notice that the hair is off. At that moment, Roto spits out the lock of hair and Tylor confesses to everything that happened that day. Fritz congratulates Tylor for being honest as it is something David would do. Plus, Cutter mentions that she has a whole bag of David's hair that he could have used. After replacing the hair, Tylor admits that he can see why they liked David as he was weird like them, pleasing Val.
Mike's Comedy Class
Mike attempts to teach the class about the concept of improv. All of his improv techniques seem to only rely on ball related imagery. When he asks the class for some suggestions, they all say cube related ones that begin to slowly annoy him.
- Billy Crystal as Mike Wazowski
- Ben Feldman as Tylor Tuskmon
- Mindy Kaling as Val Little
- Henry Winkler as Fritz
- Lucas Neff as Duncan P. Anderson
- Alanna Ubach as Cutter/Carla Benitez/Rosie
- Gabriel Iglesias as Gary Gibbs
- Bob Peterson as Roze/Bob
- Stephen Stanton as George Sanderson/Chuck
- Carlos Alazraqui as David/Josh Rivera
- Christopher Swindle as Thaddeus Bile
- Bobs Gannaway as Roto
- Hiromi Dames as Additional monsters
- Instead of the typical theme playing during the credits, an operatic choir rendition is performed with lyrics that are audibly about David.
- This is the first episode where James P. Sullivan and Mike Wazowski (not counting Mike's Comedy Class sketch) are absent. Celia Mae appears, but has no speaking lines.
- This is the last episode to feature a Mike's Comedy Class sketch.
- Josh Rivera is a reference to longtime Pixar producer Jonas Rivera.
- This is the fourth television show to use the name "Bad Hair Day", the first three being Recess, Phineas and Ferb and Imagination Movers, but the fifth Disney project to use the title as it is also the name of a TV movie.
- George Sanderson still lacks his hair and is still wearing a cone. He comments that he used to have hair, implying that he cannot regrow it, which is proven false at the end of the first movie.
- Roze now slightly appreciates Tylor as he reminds her of herself. She further comments that she was a young employee at Monsters, Inc. implying that she had another job at the company prior to taking her sister's place.
- Gary Gibbs, who first appeared in the episode "The Big Wazowskis", made a minor appearance in this episode.