Thesper, Mad Indoctrinator

When Thesper, Mad Indoctrinator enters the battlefield, it deals X damage to you and X
damage divided among any number of targets.
Players cant gain life.
At the beginning of combat on each opponents
turn, you gain control of target creature they
control with toughness less than its base
toughness until your next turn. You lose life
equal to its mana value.