You can't copyright ideas just the expression of it. So you can make games inspired by Super Mario just not use any of Nintendos characters. For example instead of italian mustachioed chibi plumber make your player character clean cut prepschool-uniformed chibi named Tim instead (but don't use my example exactly cuz it's…
Just a question: Mario, for example. Can a company, that is not Nintendo, create a character exactly like Mario and put it in a game? Of course, that would be strangely ridiculous for game industry and consumers at all, but despite that, could Nintendo do something about it legally?
Parody is a "distortet imitation". Copycat a complete character lacks the distortion. Best example maybe Wario and Mario from Nitendo itself. Wario is the evil mirror image from Mario and can be a Parody of Mario.