Superman & Bugs Bunny

The unlikely pairing of Superman and Bugs Bunny come from completely different worlds, so having them meet each other seems incredibly silly – but it did actually happen in a four-issue comics miniseries released in 2000 by DC Comics.
The meeting occurs thanks to the reality-warping craziness of DC’s Mr. Mxyzptlk and Looney Tunes’ Yoyo the Dodo. After they meet each other in a random dimension, Mxy learns that the Looney Tunes world has no superheroes and decides to let them meet some by sending them the the DC universe.
The comic has appearances from a number of characters from each franchise – the likes of Green Lantern, Marvin the Martian, Foghorn Leghorn and Plastic Man, for example – but it is Superman and Bugs who star. It’s fun, but extremely nonsensical.
