Purity

Creature - Elemental Incarnation 6/6, 3WWW (6)
Flying
If noncombat damage would be dealt to you, prevent that damage. You gain life equal to the damage prevented this way.
When Purity is put into a graveyard from anywhere, shuffle it into its owner's library.¹
Illus. Warren Mahy

Crystal Keep Rulings Summaries

• The last ability is different from a "goes to the graveyard from play" ability in that it triggers after it is in the graveyar and not as it leaves play. This means that if it lost the ability while in play, it would still trigger, but if it loses its ability in the graveyard (as with Yixlid Jailer) that it won't trigger. [Lorwyn FAQ 2007/09/25]

Format Legality	Legal in Vintage, Legacy, Extended, Standard
Printings (1/9)	Lorwyn (Rare)