New Champion Concept - Chameleonic Shapeshifter

A lizardlike creature that can shapeshift to appear as other champions. When he appears to enemies as one of their allies, he cannot attack them and they cannot attack him, just as if he were an actual ally. He also gets to use their team chat, to spy on their conversations and to sow discord. This could lead to so much mayhem as he takes the form of, say, the enemy Zoe, and then uses the team chat to convince the enemy team that the real Zoe is the impostor trying to lead them into a trap, while relaying their plans to his real team so that an actual trap can be sprung.

If that sounds OP, he can be balanced out by having extremely weak base abilities, long cooldowns during which he is vulnerable, etc.

Make it happen Rito. You know it makes sense.