Whenever you cast an Eldrazi creature spell with converted mana cost 7 or greater, you may exile Kozilek's Return from your graveyard. If you do, Kozilek's Return deals 5 damage to each creature.
1/22/2016 The last ability triggers only if Kozilek’s Return is in your graveyard as you cast the Eldrazi creature spell. That ability will resolve before the Eldrazi creature spell does. In other words, that Eldrazi won’t be on the battlefield yet and won’t be dealt damage by Kozilek’s Return.
1/22/2016 Exiling Kozilek’s Return due to the last ability isn’t the same as casting it as a spell. Cards that say “Counter target spell” won’t work.