Ball Lightning (M10) from Magic 2010, available at 401 Games Canada.

• Rarity: Rare
• Finish: Normal
• Artist: Trevor Claxton
• Card Text:
  Trample (If this creature would deal enough damage to its blockers to destroy them, you may have it deal the rest of its damage to defending player or planeswalker.)
  Haste (This creature can attack and T as soon as it comes under your control.)
  At the beginning of the end step, sacrifice Ball Lightning.