You may reveal a creature card from your hand. If you do target creature you control becomes a copy of that creature until end of turn.
I kind of want it to be only , but I also think it might cost too little.
But it costs a card. Then again, I'd hate to be on the receiving end of a 1-drop that turns into Emrakul, the Aeons Torn.
I wonder if anything could be done to turn this into "not Show and Tell 5-8".
I might limit it to green or blue creatures mostly for emrakul.
That sounds like a perfectly acceptable solution.