Superman/Batman #25, p.17

High above in the cosmos, the Joker and Mxyzptlk play a game with the lives of our heroes Superman and Batman over access to ALL the 5th dimensions magics. When Superman and Batman are dead, I (Joker) get all of your (Mxyzptlk) powers. And when they triumph, YOU will pay the price, Clown.
Mxyzptlk, in an attempt to get the heroes working together forms THE COMPOSITE SUPERMAN-BATMAN.

The Joker, follows up: HA-HA-HEE! What?! You don't think TWO can play this game, Short Round?
SNAP, and like that the Joker forms a composite of the Maximums.

MAXIMUM: Magicks! The likes of which my SISTER cannot achieve.
For while-- VIKING'S thoughts are dominant-- I can feel my allies within--
Soldier...Robot...Monster...all of them combined, making me--
The Maximum MAXIMUM!

Superman-Batman: Call yourself whatever you want to--
--IT'S NOW CLEAR FOR THIS TO END, YOU HAVE TO BE PUT DOWN.

MAXIMUM: Do your BEST, you Dirty Coward.
This day will be won by the one true ULTIMATE warrior!