A very very very brief one shot-- GOSH that was some episode today!
TMNT are the property of Mirage. The quotes spoken by the canon characters are from the show-- I did not write them. But the thoughts are what I think Splinter would think.
Splinter stood in the vast chamber that was Leatherhead's dwelling, stood before this large clear container-- stood there, with one hand pressed against the glasslike material, watching as this creature beat upon the sides, roaring and growling and trying to free itself.
"My son," was all he could say, as his gaze fixed on this thing-- this mutation of a mutation. He was vaguely aware of Raphael's hand on his shoulder; of the words of a family around him discussing the whys and wherefores and whats of their situation.
He registered it all, in the back of his thoughts, but he kept his foremost concentration on this thing-- this monster--
-- this son.
You were the first to speak. You were the first to try to imitate my own experiments in vocalization. When I realized that I could make these sounds, and attempted to do so, you were the first to perk up your ears, to watch me curiously, to listen eagerly. When I practiced my name, you were the first to say it.
This thing in the containment unit growled, snarled, frothed at the mouth; it's teeth snapped loudly against the glasslike partition but could not scratch it. Its muscles bulged and flexed and yet it could not break free.
"I know what it's like to be a monster," he heard Leatherhead say.
You are not a monster! You are my son! You tried to discover how the toilet worked. I had to mop the floor for hours. You tried to learn if things fall at the same rate of speed. You took various items from the kitchen to drop from the top bunk. I had to clean up a dozen raw eggs, as well as bathe Michelangelo since he had gotten in the way. You set fire to Raphael's blanket trying to repair his toy car, and you were barely four at the time!
You are my son Donatello!
"Poor Don," Splinter vaguely heard Raphael say.
"What are we gonna do, Leo?" Michelangelo's plaintive question reached his ears as well.
What are we going to do? We are going to care for Donatello! We are going to take care of my son! We are going to find a cure for him!
"We're going to hunt down a cure for him; no matter what it takes," Leonardo verbally answered what Splinter was thinking.
Yes-- a cure! You have found many cures, Donatello! You found a cure for our living arrangements, for our transportation problems, for our basic needs. You have found so many "cures" for so many problems! You found a way to change back those poor people you told me of, those people that the Shredder had mutated to do his bidding in that underground city!
And now you are in need of changing; now you have been mutated by the evil of another. Now you are in need of a cure!
We must find a cure!
But he stood there silently, watching as this creature tirelessly continued to batter the containment unit, never hurting itself, but attacking with all of its strength. He stood there, eyes filled with the tear-blurred image of this creature-- and in the distortion, he could see Donatello. He could see his son.
My son... my son... please come back to me.