Rosheen, Roaring Prophet is a rare Legendary Creature — Giant Shaman card from Modern Horizons 3 (MH3), collector number 202. Current market price: $0.17 (foil $0.28), TCGplayer market prices via Scryfall.
When Rosheen enters, mill six cards. You may put a card with {X} in its mana cost from among them into your hand. {T}: Reveal any number of cards with {X} in their mana cost in your hand. Add {C}{C} for each card revealed this way. Spend this mana only on costs that contain {X}.