Erika's Gym

Challenge {1}{g} (Opponents {3}{g})
Create a 3/3 Erika's Gloom token. Target
creature you control fights Erika's Gloom token.
If your creature defeats the token and survives,
you may put an indestructible Rainbow Badge artifact token onto the battlefield under your
control with "all grass creatures you control get
+2/+2." The Gloom token is exiled if you lose
the fight. No player can have more than one
Rainbow Badge under their control.