What am I

A little AU set after the events of  'Into Dimension X'

Michelangelo had just returned from being trapped in Dimension X for a few months, while there something had happened he had yet to tell his family, while he'd been awaiting on his big brothers to come and rescue him which took  a long time by the way he'd waited and waited and it took months for them to eventually come. 

It wasn't long before Mikey got himself caught and not being the intellectually gifted of souls had struggled to escape at first, the Krang had taken some of his mutagen blood & DNA and put their own DNA into Michelangelo's body using him as a guinea pig as they continued to experiment with their mutagen trying to get it to work as they wished to perfect what they planned to do with April when they got the chance.

Using the opportunity on this mutant turtle/human hybrid they had by chance captured who had been also helping thwart their every plan it was something as a gift to find him in their world but here he was and hoped to destroy their enemy turtles from within using Michelangelo as a vessel to do it. 

The result of merging Krang & the one referred to as Michelangelo's DNA was Mikey became accustomed to The Krang's universe, he understood their technology, their language & understood what they were trying to do. The Krang had by this action given an enemy their knowledge but in doing so gained vital knowledge from him in turn, that helped their own endeavours so when he escaped they were not too concerned to hunt him down they had already got what they wanted from him and set their plans in motion Michelangelo returning to earth and with his fellow turtles was in fact part of that plan. But he was focussed on why he came to rescue Leatherhead and was plotting against the Krang & their plans.

Mikey's loyalties did not shift if any thing he was more defiant now he had had a few scraps with Krang who made no attempt to recapture him & the creatures of this world and became battle hardened and gave himself the moniker 'Savage Mikey' and wanted desperately to rescue his friend Leatherhead but was now smart enough to realise he couldn't do it alone, he used the time to scout the place, learn about his new environment, get intel on his enemies how to fight and defeat each species of them and learned how things responded to sound & the different gravity and find out all he could it was a fact finding mission and also a battle to survive in such conditions.

He'd often wondered if they just couldn't find him or if they were using this presented opportunity to teach him a lesson, perhaps they were mad at him for all his 'mess ups' Mikey wondered if they'd given up on him but the optimistic Mikey dismissed that fear, they'd come he was sure of it..

The hardest part was the isolation and loneliness, he found he now questioned things that never before occurred to him, he felt now he had a useless existence compared to his brothers roles in the family, they all contributed things he couldn't : Leonardo was the most skilled ninja & leader, Raphael the best fighter and Donatello the genius who had a invention for every situation it seems Mikey questioned what he brought to the table and besides being the family cook & fun turtle & party dude & chief at naming things he decided that wasn't enough!

Then one day while Mikey was doing the rounds patrolling the area he mostly did this just to keep himself sane and give him a routine to stop him thinking too much he saw his brothers fighting a Rocktopus and not very successfully either he might add! 

Mikey made his way over and soon got the best of the alien beast, using the fountain of knowledge he gained Mikey finally reunited with his beloved bro's. 

Mikey kept his focus and played down how long he was there and not shared much of his experience while here keeping his emotions in check as he got down to business & lead his brothers towards the captured Leatherhead's location and helped lead them to both rescue him and destroy the Krang's plans & out smarting Donnie  in the process, he stepped on Leo's toes too and called the shots & Raph was impressed by Mikey's genius & when they set up the explosions to buy some time before the Krang inevitably invaded as the turtles came home through a portal after Mikey brought home a power source for Donnie's turtle Mech. 

Mikey found the adjustment difficult home, he had been altered and didn't want to tell his family instead he'd allowed his brothers to think Mikey's newly acquired 'smarts' were due to them being in crazy backwards land and in crazy backwards dude is king. And applied only when in Dimension X he tried to act like his old self.

His brothers accepted this & Mikey was happy they didn't question it further he figured he could use his new knowledge to help when the time came he hoped this could be the thing that made him special, something he could contribute, the thing that made him as useful as the rest. 

But something was brewing and that something was running through Mikey's veins in the form of turtle/human and now Krang DNA and that something was about to cause mayhem.