Chromium, the Mutable [Core Set 2019 Prerelease Promos] Darksteel and that player can't activate

and that player can't activate abilities that aren't mana abilities

One razorclaw is three bears too many

Your opponents can't cast spells of the chosen color

waiting for a victory only it can see

sacrifice Serendib Djinn

Chromium, the Mutable [Core Set 2019 Prerelease Promos] Darksteel and that player can't activateSet: Core Set 2019 Prerelease Promos Type: Legendary Creature Elder Dragon Rarity: Mythic Cost: {4}{W}{U}{B} Flash This spell can't be countered. Flying Discard a card: Until end of turn, Chromium, the Mutable becomes a Human with base power and toughness 1 1, loses all abilities, and gains hexproof. It can't be blocked this turn.