Steel Hellkite

Most colorless finishers split the work in two: a body in one slot, a mana sink in another. This collapses both into one flier and gates the payoff behind a combat-damage clause that turns the whole card into a calibrated scalpel. The destroy ability does not hit everything: it wipes only nonland permanents at exactly the mana value you name, and only from a player it connected with that turn. That double restriction (you choose one number, and you must have bitten first) is what keeps a six-mana colorless threat from being a Nevinyrral's Disk on legs. The : +1/+0 line is not idle filler. It pushes a 5/5 toward lethal in the air, but its quieter function is positional: the destroy clause keys off whatever value you name, not off the Hellkite's own power, so swinging harder in the air does not narrow or widen what the sweep can erase. The reward scales to the table: name zero, and you sweep every token your opponent left back; name two, and you take their accelerants and signets; name whatever the threat in front of you happens to cost. A 5/5 flier already pressures life totals, but the design point is that it kills incrementally and surgically, one mana value per turn, only after it has been allowed to bite. It is a removal engine wearing a beater's clothes, and the disguise is the whole reason it gets to be both at once.