Polar Knight

{x}{g/u}{g/u}: You get X {s}.
{t}{s}: Create creature token Snow Ball tapped
0/1 with "at the begginig of your untap phase,
target opponent take 1 damage".
{t}{s}{s}{s}: Tap target creature an opponent
control. That creature dosen't untap during it's controller untap step, if Polar knight on the battlefield.
{t}{s}{s}{s}{s}{s}: Destroy target creature.
"...... Hmph."