Mincho is a slime-like race whose whole body is made of mintchoco ice cream.
ICEcRIM Co., a Rimworld food company, create a slime toy for advertisement, using their top-selling product and "variant mechanite," that keeps the mixture to be like slime.
Unfortunately, during the final production stage, they have accidentally used the wrong variant of mechanite, which was planned to be disposed of due to a critical defect. As a result, what should have been slime toys, became human-mimicking, slime-like beings called the Mincho.
ICEcRIM realized their mistakes months after the production and tried to recall those "toys," but they were already delivered all over the Rim.
Mincho can change appearance by eating cookies. Mincho can also produce ice cream accordingly.