Hydra Broodmaster (JOU) from Journey into Nyx, available at 401 Games Canada.

• Rarity: Rare
• Finish: Normal
• Artist: Steve Prescott
• Card Text:
  XXG: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
  When Hydra Broodmaster becomes monstrous, put X X/X green Hydra tokens onto the battlefield.