A vague idea for a parasitic champion

So, I got to thinking, and while I don't have a 100% down idea yet of who this champion would be, I have a good idea of what their ultimate would be and I think it would be one of the most interesting ults ingame.

This champion is parasitic right? Well, what if they could temporarily (say, 5 seconds) step out of their current 'host' (whatever creature they chose to inhabit), and squeeze itself into the body of an enemy champion on the other team, as long as they are within ult range. This ultimate would have full control over that champion, but they would be unable to use items, or abilities.

This ultimate could be used in several ways, to gain sight of the enemy, to infiltrate their ranks and initiate a mutiny, or to walk an enemy straight into your team yourself. During this time, you could not see the other team's chat, and you would appear as an enemy. This ultimate could be used to turn the tides of a team fight on its head, and since it is an especially 'op' ultimate, the caster would remain vulnerable while piloting their host. As in, their body would remain behind wherever they took control. This makes using the ultimate more tricky, but it forces the player to plan and think carefully about when/how to use it.

Like I said, this idea is very vague, as I only have the idea for their ultimate, but I still think it would be an incredible one at that. What do you guys think? Comment your thoughts down below- and post your suggestions or ideas!