Comic books have always been the badlands of intellectual property law, but even by the slack standards of the industry, MF Enterprises' Captain Marvel was exceptional.
The man behind the other other Captain Marvel was Carl Burgos, who had created the original Human Torch back in 1939. Burgos had tried to sue Marvel when the Fantastic Four came out with a reworked version of Burgos' Golden Age creation (an approach that Stan Lee and publisher Martin Goodman had appropriated, with remarkable if not acknowledged fidelity, from DC's Julius Schwarz).
Perhaps it was bitterness over the suit that prompted Burgos not only to name his character after arguably the most popular character of the Golden Age (the original Marvel's titles had often outsold even Superman), but to use the names of other famous comic book characters to fill out the book.
Despite Burgos' role and a seriously goofy power (you really have to see it), this magazine came and went almost unnoticed except, according to some comic historians, by Stan Lee who immediately brought out his own Captain Marvel as soon as MF dropped the title (despite the fact that the original Captain Marvel was not in the public domain). The land grab worked, which is why DC has the right to publish the Golden Age character but not to use his name in a title.
Somehow, I suspect that Burgos didn't get a lot of satisfaction out of this particular contribution to comics history.
(If all of this isn't weird enough for you, check out the story of the MF behind MF Enterprises... Strange, strange stuff.)