That's because you run into trademark laws, not copyright. Not to mention, if you can make the case that your art of the mouse is Parody, then it falls squarely under fair use.

Here you go.

https://en.wikipedia.org/wiki/Cuphead

> The game's creators, brothers Chad and Jared Moldenhauer, took inspiration from the rubber hose style of the golden age of American animation and the surrealist qualities of works of Walt Disney Animation Studios, Fleischer Studios, Warner Bros. Cartoons, MGM Cartoon Studio and Walter Lantz Productions.

Even more famously: https://en.wikipedia.org/wiki/Fogerty_v._Fantasy,_Inc.