Silumgar Assassin (Commander 2019 128) - Rare Magic: The Gathering Card

Creatures with power greater than this creature's power can't block it.
Megamorph (You may cast this card face down as a 2/2 creature for . 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.