Another Half Baked Champion Concept

So, I know how riot usually only takes a few things from a champion concept, so I'm here to suggest (Mainly) just a core concept. Ap Tank for top, who when attacked gets a flat # of ap based on the strength of the attack. Or it doesn't have to work like that. But the champion would basically revolve around the idea of using other champ's attacks, storing them, then sending them right back out. I thought it could be cool.

The name I was picturing was "Fission" like the process of turning matter to energy. Just thought it could be cool.

Oh, and also the ulti could duplicate the spell it was last hit with and absorb the damage (That doesn't mean take the damage form the ability), so you could take karthus's ult at the last second and send it right back. It would be hard to balance correctly, but this could be a really neat champion.