Pox (1st Place) (Arena League) [Oversize Cards] Condition:Damaged You can discard 1 WATER

You can discard 1 WATER monster to the Graveyard to destroy 1 face-down card

but how could that be

Set: Pro Tour Promos Type: Enchantment Rarity: Rare Cost: {3}{G}{W} Creatures you control get +1/+1

Set: Masters 25 Type: Legendary Creature — Elemental Rarity: Mythic Cost: {G}{U}{R} Protection from white and from black

Set: EX: Holon Phantoms Type: Colorless Rarity: Holo Rare Retreat cost: Colorless

Pox (1st Place) (Arena League) [Oversize Cards] Condition:Damaged You can discard 1 WATERSet: Oversize Cards Rarity: Rare Each player loses 1 3 of his or her life; then chooses and discards 1 3 of his or her hand; then sacrifices 1 3 of the creatures he or she controls; and then sacrifices 1 3 of the lands he or she controls. Round each loss up.