Vigorspore Wurm (GRN) from Guilds of Ravnica, available at 401 Games Canada.

• Rarity: Common
• Finish: Normal
• Artist: Jason Felix
• Card Text:
  Undergrowth — When Vigorspore Wurm enters the battlefield, target creature gains vigilance and gets +X/+X until end of turn, where X is the number of creature cards in your graveyard.
  Vigorspore Wurm can't be blocked by more than one creature.