Cavern of Souls [Ultimate Masters] Aether Revolt Prerelease Promos put a +1/+1 counter on

put a +1/+1 counter on each creature you control

If you do and they guessed wrong

Set: Friday Night Magic 2002 Type: Instant Rare Cost: {1}{U}{U} Counter target spell

Set: Odyssey Type: Sorcery Rare Cost: {3}{B}{B} Exile all cards from target player's graveyard other than basic land cards

Consul Flagship enters the battlefield or attacks

Cavern of Souls [Ultimate Masters] Aether Revolt Prerelease Promos put a +1/+1 counter onSet: Ultimate Masters Type: Land Mythic Cost: As Cavern of Souls enters the battlefield, choose a creature type. {T}: Add {C}. {T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.