Boros Mastiff is a common Creature — Dog card from Dragon's Maze (DGM), collector number 1. Current market price: $0.14 (foil $0.24), TCGplayer market prices via Scryfall.
Battalion — Whenever this creature and at least two other creatures attack, this creature gains lifelink until end of turn. (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)