Shriekmaw [Lorwyn Promos] SWSH038 where X is the highest

where X is the highest mana value among artifacts you control

"The Shaman waved the staff

Set: Oath of the Gatewatch Type: Legendary Enchantment Rarity: Rare Cost: {G} When Oath of Nissa enters the battlefield

but not for the skill to wield it

If this Synchro Summoned card is destroyed: You can destroy all face-up cards your opponent controls

Shriekmaw [Lorwyn Promos] SWSH038 where X is the highestSet: Lorwyn Promos Type: Creature Elemental Rarity: Rare Cost: {4}{B} Fear (This creature can't be blocked except by artifact creatures and or black creatures.) When Shriekmaw enters the battlefield, destroy target nonartifact, nonblack creature. Evoke {1}{B} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)