Mind washer/soul stealer/something along those lines
What this proposed troop would do is infiltrate the defending clan castle and turn the clan castle troops against their own base. This would have to be done before the first actual troop was placed because in order for this to work, the troops need to be in the clan castle. This troop would have zero health, do zero damage, and be undetectable by defensive towers. Given its circumstances, it will cost a considerable amount of dark elixir. That can be up for discussion as I'm not sure on an exact value. But it should be on the higher end considering its unique ability! If anyone else has any ideas, let the flow! I think this is a great idea! I'm sorry to anyone who had this sort of idea before I do, if anyone did!