A True 'Transform' Champion

I feel like the space in LoL for Transform concepts isn't yet filled. We have a bunch of champions with back-and-forth kits. But still no champion that really becomes someone - or something else - at some point in a game, and can't go back.

I created a concept for a champion to illustrate what this could be like;

http://boards.na.leagueoflegends.com/en/c/skin-champion-concepts/EQ9Uqdos-jonah-the-darkin-scourge

Would a champion that turns into something else permanently work in League?