Mystery Booster Playtest Cards 2021

World Enchantment

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.

Problematic Volcano

Creature — Bear Snake Mutant

{1}{Z}: Put a +1/+2 counter on Experiment Five. ({Z} is paid with one mana from any source that could produce two or more colors of mana.)