Helm of Obedience [Alliances] Fighting[×2] Metal[×2] Set: HeartGold & SoulSilver: Black

Set: HeartGold & SoulSilver: Black Star Promos Type: Fighting Rarity: Black Star Promo Retreat cost: Colorless

you may exile it

Set: Sun & Moon: Black Star Promos Type: Fire Rarity: Promo Retreat cost: 4

Set: EX: Crystal Guardians Type: Water Rarity: Holo Rare Retreat cost: Colorless

Set: Zendikar Type: Creature — Goblin Berserker Rarity: Mythic Cost: {R}{R} Double strike

Helm of Obedience [Alliances] Fighting[×2] Metal[×2] Set: HeartGold & SoulSilver: BlackSet: Alliances Type: Artifact Rarity: Rare Cost: {4} {X}, {T}: Target opponent mills a card, then repeats this process until a creature card or X cards have been put into their graveyard this way, whichever comes first. If one or more creature cards were put into that graveyard this way, sacrifice Helm of Obedience and put one of them onto the battlefield under your control. X can't be 0.