Potion of Dragons' Flame

When Potion of Dragons' Flame enters the battlefield, tap it and exile a mountain you control as an additional cost.
{t}, Discard Scale of Dragon from your hand, return the mountain exiled with this card to the battlefield. Sacrifice Potion of Dragons' Flame then it deals 8 damage divided as you chose among any number of target creatures or players.
When it comes off the fire, there is no stopping it.