McCree, Dueling Savant

McCree, Dueling Savant doesn't untap during
your untap step.
At the beginning of each end step, add two
deadeye counters onto McCree.
You may untap McCree at any time and deal X
damage to all opponents and all creatures your opponents control, where X is the number of
deadeye counters on him.
After McCree becomes untapped, transform
him.