Boulderfall

Eight mana for five damage is a rate that says everything about where red is allowed to spread its burn. Focused efficiency lives at the bottom of red's curve; the moment a spell wants to hit any number of targets at once, the color pie taxes it hard, and this is what that tax looks like at full weight. The division clause is doing the real design work: a strict single-target version at this cost would be a nonstarter on every axis, but splitting five points however you like turns the card into a slow, deliberate sweep against a wide board of small creatures. Instant speed is the one concession that keeps it from being pure ceremony, letting the split fall in response to an attack step rather than committing on your own turn. It belongs to a long line of red designs that grant "deal X across multiple things" only in exchange for a top-heavy cost, a corrective to how cheaply red gets to point damage at a single face. The five-damage budget spread among any number of targets is generous flexibility wrapped in a mana value almost no deck builds toward on purpose; the effect is real, the price is the entire point, and reading it any other way misses what the card is a statement about.