Secretive Replicant

Megamorph {1}{u/b}{u/b} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Secretive Replicant is turned face up, Counter target creature spell unless its controller pays {3}.
Changeling (This card is every creature type.)