Rob Lafratta is a UI designer in Befordshire, UK, currently working at Design Agency. Lafratta did a cool Super Mario Bros. and Marvel Comics mashup by dressing up Mario and Wario as superhero and supervillain rivals. There's Mario as Superman vs. Wario as Lex Luther. Batman Mario vs. Joker Wario. And my favorite, Wonder Woman Mario vs. Wario Cheetah.
Check out the actual site that Lafratta designed for this project. There are several other Mario vs. Wario rivalry mashups, plus the site is just slick.
And if you want a taste of what it's like to manipulate Mario's world, Sean Colleli reviewed Super Mario Maker, which is "a heck of a first effort from Nintendo" when it comes to level editors.
[Thanks, Taxi.]