Questionable copyright in comics.
 

So it's well known that Marvel and DC have somewhat questionable copyright policies. Normally they get to keep the character rights due to work for hire contracts. But there examples of a publisher claiming copyright with more ambigious justification.

For example, Marv Wolfman sued Marvel when they licensed Blade to a movie studio. His reasoning was that he never signed over the character to Marvel in the first place, he just allowed further use of Blade in comics. The judge decided that, because the movie was different from how Wolfman depicted Blade, the movie wasn't breaking any copyright law.

Which in turn leads to questions like:
Is Wolfman payed royalties for Blade?
Can Wolfman publish his own Blade comics if he wanted?
How different is different enough?