Problematic Volcano is a rare World Enchantment card from Mystery Booster Playtest Cards 2021 (CMB2), collector number 60. Current market price: $0.19, TCGplayer market prices via Scryfall.
When Problematic Volcano enters, it deals 4 damage to any target. Then, starting with you, each player assigns their creatures to the left or right of the volcano. Creatures enter to the left or right of the volcano. Creatures can't block creatures on the other side of the volcano.