Krath, the undying

+2: Destroy all other planeswalkers, Krath, The Undying gains 2 consumption counters for each permanent destroyed this way
-4: Deal 6 damage to 6 targets, you gain 6 life, activate only if Krath has 4 or more consumption counters
-10: Transform Krath Activate only if it has 10 or more consumption counters