In the first film, Celia is celebrating her birthday, so Mike invites her to a Japanese restaurant called Harryhausen's (named in honor of legendary stop motion animator Ray Harryhausen), but due to Boo being in the restaurant, the place is contained by the CDA. One device that is made to make a large dome that would get rid of fatal germs, but could harm people without CDA armor, which is why Celia comes back to work the next day with serious injuries. She is initially upset with Mike and complains about how the date was ruined, but when she sees Mike in danger of being captured by Randall for devious purposes, and when Mike reassures his love for her, she saves Mike by subduing Randall with a crowd after she feign-announces him breaking the all-time scare record. She is seen again at the end of the film, having fully recovered and made amends with Mike, and tells him that a box full of magazines has just arrived. Both she and Mike are surprised to see that Mike has made the cover of the magazine. She kisses him and her hair tickles his face.
The year before the film takes place, she and Mike are supposed to have won the 7-legged race at the year's company picnic.
She also appears in the company play Put That Thing Back Where It Came From Or So Help Me that stars her boyfriend, who has also written, directed, and produced the play.
Celia makes a very minor appearence in the ride. Her voice is heard over the intercom telling the guests when they can eneter the laugh floor.
- Celia's name may be a play on the word "Cecaelia." It might also refer to Scylla, a monster in Greek mythology known for snatching up those who strayed too close to her with mouths attached to tentacle-like limbs (somewhat like Celia's snakes).
- According to the book Monsters Inc.: The Essential Guide, the five snakes serving as Celia's "hair" are named Amelia, Bobelia, Ophelia, Cordelia, and Madge.
- Celia might or might not appear in Monsters University, but her name may be said in the movie. She might also be Mike Wazowski's sweetheart, but they might not say her name.
- Celia's age, according to the handbook, is probably 24. Mike might also be 24.
- Celia's appearance resembles to the Greek mythology legend, Medusa. They share some similarities and differences.
- They both have snakes for hair.
- Medusa has two eyes but Celia has one.
- Medusa turns people into stone by looking into her eyes but Celia doesn't have this ability.
- Celia is nice but Medusa is bitter.