Molten-Tail Masticore is a mythic Artifact Creature — Masticore card from Scars of Mirrodin (SOM), collector number 177. Current market price: $0.41 (foil $0.97), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, sacrifice this creature unless you discard a card. {4}, Exile a creature card from your graveyard: This creature deals 4 damage to any target. {2}: Regenerate this creature.