Silumgar Assassin (128) [Commander 2019]

Creatures with power greater than this creature's power can't block it. Megamorph {2}{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 this creature is turned face up, destroy target creature with power 3 or less an opponent controls.