Make a mouse cartoon in the style of Disney and tell me how well that goes down.

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.

Plagiarism is very much a matter of copyright, not trademark infringement:

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

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.

There is a conspicuous lack of mice in that cartoon.

In music it sometimes isn't.

https://en.wikipedia.org/wiki/Midler_v._Ford_Motor_Co.

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

Even if it were (which I am not competent to speak on), should that help to enrich some large corporation, for example?