Chandra, Hail of Fire

+2: Deal X damage to target creature where X is how many mountains you control.
-4: Put a 5/5 Fire Elemental Token onto the battlefield under your control. If you have 4 of these sacrafice them and deal 20 damage to target player
-15: Deal 10 damage to target player for every planeswalker you control. If you control more than 5 planeswalkers you win the game