Chandra, Unrested Soul

+2: Sacrifice a permanent you control and make X 2/1 Elemental token creatures where X is half that cards converted mana cost (round up)
-3: Sacrifice an Elemental you control and put to the side near your deck. You gain life equal to its Power.
-10: Return all Elemental token creatures you sacrificed to the battlefield, they have haste and you gain 1 life for each card returned this way