Dagoth-Ur

When Dagoth-Ur enters the battlefield, for each opponent, tap up to one untapped creature you control. When you do, gain control of target
creature that player controls with power less than
or equal to the tapped creature's power for as
long as you control Dagoth-Ur.
Whenever you attack with a creature an opponent
owns, you gain 2 life and that player loses 2 life.