A champion who can disguise as a different champ...

Just a thought that could make a really cool signature move for a new champion. His/her ult could be to change its outward appearance in every way (health bar, champ/skin appearance, etc.) to look like somebody else on the team. The idea is that when the team is going for a team fight, it uses the ability to look like the ADC but is really built like a tank and the enemy is not sure to attack the fake or the real ADC. Not fully thought out, but I think it has huge potential - a bit different from typical stealth, teleporting, jumps and other common moves for deception.