Wurm's Tooth [Magic 2011]

Set: Magic 2011 Type: Artifact Rarity: Uncommon Cost: {2} Whenever a player casts a green spell, you may gain 1 life. "The great wurm bit down on me. Instead of being crunched bloody, I slid into the space where its tooth was missing. One tooth—a boon most potent, indeed." —*The Tall Tales of Oleander*