Her first appearance was in Episode 14, Hello, Sailor Mini Moon. Like all the other witches except Eugeal, she is shadowed for most of the time. Her first unshadowed appearance is in Episode 21, Destiny's Arrival, when she is overheard by Eugeal saying that Doctor Tomoe might want her to replace Eugeal. She is also the one who put snails in Eugeal's locker and tacks in her shoes.
On the island where Eugeal seeked out the Pure Hearts she knew were the ones they were looking for, Mimet put acid snails in Eugeal's car to dissolve the brakes. When Eugeal drove her car away after being defeated, the loss of the brakes caused her to crash over a cliff to her death.
From here, Mimet was assigned to extract Pure Hearts to feed to Mistress 9. She would always carry a Daimon Heart Snatcher (created by Doctor Tomoe in his Heart Snatcher oven) in an attache case, while targeting attractive male celebrities. She would send the Daimon to suck out the victim's Pure Heart through his mouth, but the Daimons would always be destroyed by Sailor Moon, and the Pure Hearts returned. Her Daimons included Western, Uhenshu, Uta, Utomodachi, Ubara, Undohkai, and Uchoten.
At one point, when Doctor Tomoe was out of the house, Mimet crammed the Heart Snatcher Oven full of board games, causing it to malfunction and trap the house in another dimension, and creating the Daimon, Ikasaman. The house was returned to normal when Sailor Moon destroyed Ikasaman.
After Uchoten was destroyed, Doctor Tomoe decided to give the next assignment to Telulu. Mimet overheard this and used a voice imitator to change her voice to Tomoe's and tell Telulu that the project was canceled. She then took Telulu's job, sending the Daimon Upasocon, but Sailor Moon destroyed her. Mimet then took out Eugeal's power device, and entered it to appear on a giant TV screen, increasing her size and power. However, Telulu appeared, having found Mimet out for stealing her job, and explained that Eugeal never used her power device because if the plug is pulled while she is inside it, she would be forever trapped inside it, killing her. Telulu pulled the plug, causing Mimet to fall into nothingness.
Mimet uses her staff to shoot a star beam called Stage Fright, which can disorient people or knock them out.
- The way Mimet dies at the end is similar to Emerald; both are depicted falling into a black hole.