Genius Girl

The Genius Girl is a character introduced in Mario + Rabbids Kingdom Battle, appearing only during the introductory cutscene. She is the inventor of the SupaMerge and an avid fan of the Mario franchise, decorating her entire workshop with Mario merchandise.

The Genius Girl invented the SupaMerge with the intent to solve an energy crisis, but it had a problem with overheating. After she left to take a break, the Rabbids showed up in their Time Washing Machine. One of them, who would later be named Spawny, found the SupaMerge, using it to fuse other Rabbids with several objects in the room (creating Rabbid Peach and Rabbid Mario in the process) before accidentally hitting the Time Washing Machine, causing it to malfunction and transport both her robot assistant, Beep-0, and the Rabbids to the Mushroom Kingdom.

In Mario + Rabbids Sparks of Hope, she is implied to have been the sender of the message in the Memory "A Message From An Outer Dimension", though JEANIE does not know who sent it.