When the "Ultimate Drako" attacks the lair, he sends each of the turtles to another world or an alternate universe (Splinter is sent to the Battle Nexus, and Casey is just left in the lair, wondering where everyone has gone). In this universe Michelangelo had lost an arm at some point (however, he is still incredibly skilled with his nunchucks, possibly even better than his normal self) and is covered in scars. This Michelangelo seemed to have matured a great deal, since he didn't have his trademark humor. He was in fact, very serious.