Miraak, the Last Dragonborn

Deathtouch, Flying

When Miraak, the Last Dragonborn enters the battlefield, you may sacrifice a Dragon. If you do, Miraak gains the "Toughness" and "Power" of the sacrificed Dragon until end of turn.

{b}: Sacrifice another creature. Miraak deals damage equal
to that creature's power to any target.

Miraak, the Last Dragonborn has power and toughness equal to the total power of all Dragons you control.