Marcor, Captain of the Jerus

When another creature enters the battlefield, you may pay an additional {w}{r}. If
you do, put a number of +1/+1 counters on Marcor equal to that creature's power.
All creatures you control get +1/+1 for each +1/+1 counter on Marcor, and have vigilance, haste, and shadow.
"We shall triumph, not because of our vast army or stealth, but because we are stronger than you."
-Marcor, to Ydoplus