Airgon, the Blight Dragon

Haste, Trample, Deathtouch
When Airgon, the Blight Dragon enters the battlefield, tap all target creatures that an opponent controls. That creature doesn't untap during its controller's next untap step.
Airgon, the Blight Dragon's power and toughness are each equal to the number of health you currently have. This may change throughout the course of the game.
As the sun goes down, the danger rises from behind the mountains. Best hope you live far away.