T.H.U.D. Cannon

T.H.U.D. Cannon enters the battlefield tapped
and doesn't untap during your untap step.
Titanfall - Whenever a creature or vehicle
with base power 5 or greater enters the battlefield
under your control, untap T.H.U.D. Cannon.
{t}, Sacrifice a creature: T.H.U.D. Cannon deals
damage equal to the sacrificed creature's power to
any target.