Obosh, the Preypiercer

Odd mana values only is a savage tax: no two-drops, no signets, no even curve to enable double-spell turns, and half your usual removal suite gone. What you buy with that restriction is a damage doubler that scales with the very deck the restriction forces you to build. Every burn spell, every combat swing from an odd-cost creature, every ping and reach effect off an odd-value source resolves for twice its damage, and because the deckbuilding rule guarantees your board is stocked with qualifying sources, the payoff behaves like a floor rather than a ceiling. That is the elegant part: constraint and reward run on the same axis. The thing that shrinks your card pool is the thing that guarantees the doubling applies.

Worth being precise about how the ability works, because it is easy to misread. It is a replacement effect, not a trigger: it does not go on the stack and it cannot be responded to, it simply rewrites the damage event as it happens. And it keys on the source's mana value, a fixed property printed on the card. Auras, anthems, and counters change power and toughness, but mana value is untouched, so a buffed odd-cost creature still qualifies while an even-cost one never does no matter how much you pump it. It reads as a red aggro accelerant, and it can be, but the sharper builds lean on repeatable odd-cost pingers, where doubling small increments compounds toward lethal faster than the raw numbers suggest. The 3/5 body is almost incidental. The card is a rule your deck agrees to live under, stapled to a Hellion Horror.