And what stops you from making new content with Mickey Mouse in it is the set of copyrights Disney holds on Mickey Mouse. The trademark does nothing.

Established law says that every publication of a work involving a copyrighted character creates a new version of that character whose copyright extends for the full period starting from the publication of that work. This came up when someone wrote a story about Sherlock Holmes, who was out of copyright, and they were sued, successfully, on the theory that they had used aspects of Sherlock Holmes' personality that were developed in stories still under copyright.

Sam Logan had some fun with the concept here: https://www.samandfuzzy.com/3429

> After nearly 100 years of acting, what's your favorite of your roles?

> Steamboat Willie.

> Really? Not any of your other--

> We don't talk about my other roles. They're a burden. A liability, used to control me. I have left them behind, so that I may be free.