World War Hulk

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) [I] The next red or green creature spell you cast this turn can be cast without paying its mana cast. [II] Put three +1/+1 counters on target creature you control. [III] Choose target creature you control. Until end of turn, double its power and toughness and it gains trample.