What would happen in practice if someone tried to use the public domain Mickey for something? I assume that regardless of the legal status, you'd still have a f

What would happen in practice if someone tried to use the public domain Mickey for something? I assume that regardless of the legal status, you'd still have a fun time with Disney lawyers proving in court that you had the right to use public domain Mickey. Is Mickey also a trademark (which never expires) and anything using public domain Mickey would be too similar to their trademark?