Mika features solely in the second OVA episode of *Rei Rei* as Satoshi's girlfriend. The young, geeky Satoshi discovers a discarded promo and visits the fortune teller Kaguya, accompanied by Mika and witnessed by Kaguya and Pipi. During this meeting, Mika voices intense frustration with their relationship. She confronts Satoshi about his habit of only taking her to places that interest him—video game stores and the planetarium—while disregarding her preferences. Mika further highlights his consistent refusal to engage in romantic gestures like holding hands or physical advances, interpreting this as immaturity and disinterest. Her dissatisfaction peaks when she angrily ends the relationship, insulting Satoshi as "clueless, boring, immature, and probably impotent" before storming off.

This rejection profoundly impacts Satoshi, causing an emotional breakdown observed by Kaguya and Pipi. His resulting distress and retreat into video games lead to his soul becoming trapped within a game's software, forcing Kaguya and Pipi to intervene. Mika's actions directly trigger Satoshi's crisis and the ensuing supernatural events, including the game's tentacle monster and the rescue mission for his soul.