Mouse-Zilla is an enormous robotic mouse created by Tobey during his collaboration with Dr.
Two-Brains. It's built in a similar style to his other robots, with multi-jointed arms, shoulder guards, and an antenna on its head. However, in addition to being definitely more mousey than his more humanoid creations, Mouse-Zilla is made with a special kind of flexible yet sturdy metal created by Two-Brains. Mouse-Zilla also features several quirks, like extendible grabbing whiskers (added by Two-Brains) and an energy-bubble-making machine on its nose (added by Tobey). Mouse-Zilla first appeared in the episode named after it, "Mouse-Zilla". It was mainly used, throughout the duration of the episode, to break into cheese reserves throughout the city and steal all of their contents, though Tobey wanted to use his creation to destroy the "really tall state building".
So far, Mouse-Zilla is the robot that has come the closest to destroying WordGirl. It managed to capture her in its extendible whiskers and would have crushed her if it weren't for Captain Huggyface stealing the remote and commanding the robot to release her.
At the end of the episode, WordGirl throws Mouse-Zilla into the city's bay. However, Mouse-Zilla survived and later made a cameo appearance in The Rise of Miss Power alongside some of Tobey's other robots.
The name Mouse-Zilla is a parody of the Japanese movie monster Godzilla.