Can we finally have a gaseous champion?

Ok so what I was thinking is that we have liquid like champs such as who can turn into a liquid. But how about we have a champion that can go through units and terrain in a gaseous form. ^.0?

So the champ may be permanently in a gaseous form which I think would be cool and can go through units damaging them. His ult can go into a enemy champion and temporarily take control of them for 3 seconds slowly killing them from inside and allowing him to use his abilities from that champion. He is invulnerable whilst inside an enemy. http://38.media.tumblr.com/f36373be357a72d3318f910d35f603e8/tumblr_n5zlnmUi8Q1r6n45qo1_400.gif