Beeswax's Ultimatum

Until the beginning of your next upkeep, whenever a nontoken creature enters the battlefield, put a 0/2 blue Mutant creature token with evolve, a 1/1 blue and green Mutant creature token with evolve, and a 2/1 green Mutant creature token with evolve onto the battlefield.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)