Mitzi Mozzarella was the only female member of the Rock-afire Explosion. Over time she was developed into a character designed to be a important role model for young girls1. She was also strongly promoted by ShowBiz, being heavily featured on merchandise that was targeted toward girls.
Like most of the other characters, Mitzi's origins began with The Wolf Pack 5. The female character from The Wolf Pack 5 was fox named Queenie, however when the band was placed into the first ShowBiz Pizza Place, executives from ShowBiz requested that she be changed into a mouse to go along with the "pizza" theme of the restaurant2 (and quite possibly to play off the connection of the already popular character they were competing with, Chuck E. Cheese). Creative Engineering reluctantly agreed to make the change, and Mini Mozzarella was born. The only ShowBiz location to ever use The Wolf Pack 5 was the original store in Kansas City, so the Mini Mozzarella character was exclusive to this location.
When the Rock-afire Explosion was developed, Mini became Mitzi. She was given a cheerleader's outfit, complete with saddle shoes and matching pom-poms. It was still a play on the 50s-style character of Mini, but this new appearance had a broader range of appeal. In the beginning, Mitzi played a rather small part in showtapes and had almost no speaking roles. Aaron Fechter was Mitzi's original voice, which was high-pitched and squeaky and didn't lend itself to songs very well. Briefly in 1982, Mitzi was voiced by Monique Danielle3, who portrayed the character very closely to Aaron's original vocals. It wasn't until late 1982 when Shalisa Sloan at the young age of 11 took over as the voice of Mitzi that her character truly began to take shape.
Shalisa was quite the vocal prodigy, and because of her age, she gave Mitzi a sense of innocence that breathed some much needed believability into the character. Mitzi began to take on a personality of an actual young girl of the 80s. She started singing pop songs that children of the time could relate to, making her a favorite among kids. In fact, a few times actual references to Shalisa's age were placed into showtapes - making her the only character to actually age from year to year. Other aspects of Shalisa's personal life were also integrated into recordings and became part of Mitzi's character (such as being the captain of her dance team, president of student council, etc). Because she was presented as being younger than the others, Mitzi was sometimes laughed at for making mistakes, and the other characters were notorious for making little comments at her expense4.
Mitzi was one of the few characters to have a "2nd generation" animatronic in development. Creative Engineering, Inc had been given funds from ShowBiz for research and development, and these funds were poured into making more advanced animated characters. A newer version of Mitzi was created that had a bendable waist and arms that could reach around in front of her, enabling her to actually dance on stage. Unfortunately due to budget cuts within ShowBiz, this second version of Mitzi never made it past the prototype stage2.
It should be noted that Mitzi's character and relevance to young girls was valued by ShowBiz so much, that it was held onto even after Concept Unification removed the Rock-afire Explosion from their restaurants in 1990. Her cheerleader persona was more or less transplanted onto Helen Henny and lives on to this day5. After the end of the Rock-afire Explosion's run at ShowBiz, Mitzi became part of the New Rock-afire Explosion along with the rest of the characters6. Her new 'mijjin' sized character was typically adorned in a black shiny dress, and often times did not have her traditional blonde wig.
Mitzi has always been a fan-favorite and to this day remains one of the most revered Rock-afire characters. Shalisa James (Sloan) still periodically voices Mitzi, and has helped to record entirely new shows such as "Hips Don't Lie" in 20087.
1 - 1983 ShowBiz Pizza Place Lunch Tours Promo (Long Version)
2 - ShowBizPizza.com Correspondence with Aaron Fechter
3 - Archival Home Video - "Monique Danielle Audition"
4 - Showtape Review - Rock-afire Explosion Showtapes
5 - ShowBizPizza.com Correspondence with Jul Kamen
6 - CEI 20th Anniversary Promo Kit
7 - Rock-afire Explosion - Hips Don't Lie