Moonveil Dragon

The triple-red pip in the casting cost is the first signal that this is a finisher built for a deck already drowning in mountains, and the activated ability is what that commitment buys: a Fireball-shaped overrun that scales with how much red mana is left after the dragon resolves. The pump is power only, no toughness, so it does nothing to keep your board alive through combat; it is purely an offensive lever, the kind of effect that turns a stalled ground full of small bodies into lethal in a single attack step. Where most red haymakers spend their mana the turn they cast, this one converts every untapped mountain on the following turns into incremental damage across the whole team, a repeatable anthem that only ever points forward. The body itself, evasive and reasonably sized, gives the deck a clock independent of the ability, which matters because the +1/+0 trick is a mana sink rather than a guaranteed payoff. It belongs to a recurring class of red top-end designs that reward going wide and mono-color: the more creatures and the more red sources you have, the more lopsided each activation becomes. A control deck would rather have a counterspell here; a token-heavy or aggressive red deck reads this as the button that ends the game.