Xavak, The Rapacious

Flying, When entering the field or attacks, you
may tap or untap a target creature. If tapped, it
doesn't untap its controller's next untap step.
{3}: Control target tapped creature Xavak has ever tapped. It gains flying. If three opponent's tapped creatures are controlled by you simultaneously,
draw a card.
Invasion-Should you have at least 12 Aliens, and
Xavak on the field at once, all instantly untap, get
+1/+1 flying, and Vigilance, and attack, bypassing
First Strikes & don't