Roz's History
Monsters, Inc.
Roz appears to be the key master and administrator for Scare Floor F, holding all the keys to children's closet doors at Monsters, Inc. She is responsible for all the paperwork done by Mike, and she often works at an office near Scare Floor F that can be separated from the rest of the factory via a retractable shutter.
At the start of the film, Mike visits Roz in her office to receive his dossiers on his and Sully's children to be scared, only for Roz to interrupt him, reminding him that he failed to turn in his paperwork last night. Though Mike expressed indifference to her concerns, Roz sternly warned him against letting it happen again. As Mike took his leave, Roz warned him she was keeping an eye on him only for Mike to secretly say that she's nuts.
Roz later accosts Mike at the end of the shift, guessing from his excited outlook that he had a fun-filled evening planned, and casually asked if he had turned in his paperwork. She then departed as she sarcastically noted his awkward silence spoke volumes.
The next day, Mike approaches Roz to mention that Randall was working late on the Scare Floor last night and requested the card key for the door he used. Roz ignored his request, being more concerned that he failed yet again to turn in his paperwork. She then proceeded to slam the shutter shut on Mike's hands, crushing them and making him scream in pain.
At the end of the film, it turns out that Roz is Agent #000001 of the Child Detection Agency, who had been working undercover in the factory for two and a half years to investigate the abuse of the closet doors. She remarked that all her hard work was nearly wasted when Sulley and Mike came into possession of Boo but acknowledges that without their aid, she never would've discovered Randall and Mr. Waternoose's plan. She gives them both five minutes to say goodbye to Boo as they return her to her room, then observes as the door is shredded. Afterward, Roz says she doesn't want to see any paperwork about Boo's invasion, contrary to her requests earlier in the film, which ironically started this whole caper.
She is not seen again for the rest of the film, but frequently appears in the film "outtakes". One example is when she unexpectedly pops out of the toilet and startles Sulley, who has opened the bathroom door to get Boo. Another is when the CDA agents surprisingly find her taking place of George Sanderson after he gets his fur shaved off and is showered. The third is when Sulley tries to show Boo that the closet is empty, only to find it occupied by Roz saying "Guess who!" In all three outtakes, Roz makes her infamous laugh, "Ahh-ha-ha!" and sends others bursting into laughter.
Monsters University
Roz makes a quick cameo in Monsters University when Mike and Sulley are able to escape the human camp and are taken by the CDA. She is shown dressed up as a CDA agent with her uniform covering her entire body except for a transparent glass "dome" revealing her hair, but her size and voice still serve as a giveaway. When Terri asks what's going to happen to them, Roz states that Dean Hardscrabble will decide that. But to rest assured, she then adds that they'll be watching them, "Always watching," foreshadowing her role in Monsters, Inc.
Monsters at Work
In the pilot episode, "Welcome to Monsters, Incorporated", the day after Waternoose's arrest, Roz speaks to Mike and Sulley to inform them that the board of directors were placing the two of them in charge of Monsters, Inc. As she took her leave, she added that her sister Roze would be taking her former job and forewarned that Roze was not as "bubbly" as herself. In the season finale, "It's Laughter They're After", she is revealed to also be a member of Monstropolis Energy Regulatory Commission (MERC), and informs Mike and Sulley that the board of directors claim that Monsters Inc isn't producing enough power with laughter, and orders them to produce 1,000,000 "gigglewatts" of power by the end of tomorrow, otherwise all power will move to rival company, Fear Co.. Near the end of the episode, a triumphant Mike ask her where Roze is, and claims that called in sick that day, much to Mike suspicions.
