Creatures with power greater than Silumgar Assassin’s power can’t block it.
Megamorph 2B (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 Silumgar Assassin is turned face up, destroy target creature with power 3 or less an opponent controls.