New champ idea (not a practical one though)

What if there was a champ that would take the form of the last champ that he/she killed? So for example, if I were to kill a blitzcrank, I would "shapeshift" or copycat the same abilities as the blitz I just killed. But I think this would be a bad idea bc idk how the items would work (switching from ad/ap/tank) but I'm just saying it would be fun to play a champ that could be different champs throughout the game. And in no way am I implying Riot SHOULD make a champ like this, I'm just throwing an idea out there :)