An advantageous genetic condition bestowed only upon the most ultimate, sweetest, most radical, semi-mammals, semi-ninja ninjas. Having Nindrome means you can kill people and not even care, and also you flip out anytime and fly through people. Not around them, through them.
"Whoa, dude! Did you see that rad person with Nindrome? He was totally throwing ninja stars at other undiscovered galaxies because someone in Canada was picking their nose. There was fog everywhere and a guitar started wailing so loud from Peru that you could hear it."
"Yeah, yes, I saw him. My friend Jason was really sick for a while, but it turns out he has Nindrome too. He was in the hospital for 2.5 seconds and then destroyed everyone in the hospital except for the hot nurses and boss dogs. Jason's so lucky..."