Remidy, the lost Wanderer

+3: you draw 1 card, each opponent discards a card, you may play an extra land this turn
-X: Tap X target Creatures, you may untap X target creatures as well. Put X +1/+1 counters on target creature. You gain X life.
-15: Multiply the loyalty of all other planeswalkers you control and power of all creatures you control by X. X is your lands - target opponents lands