Lilly, Ghost of the Sands

+3: Activate this ability when Lilly, Ghost of the Sands enters the battlefield: Lilly, Ghost of the Sands has hexproof. Gain three life.
-4: Gain four life. Target creature gets +2/+3, Flying and Hexproof.
-12: Destroy target creature, you gain life equal to both that creatures power and toughness.