Deathleaper, Terror Weapon

Flesh Hooks reads the summoning-sickness clock as a permission instead of a penalty: any creature you control that entered this turn gets double strike, continuously, for as long as this stays in play and the turn lasts. That single-turn window is the whole design axis. The board you built incrementally gets nothing; the payoff lands on the turn you empty your hand, unfurl a wide token wave, or resolve a mass reanimation, so every body arriving alongside the swarm that can attack connects twice. Haste means the anthem itself swings the moment it lands rather than waiting a turn, and flash is what lets it hold in reserve, dormant in hand until the swarm suddenly exists. That flash clause also opens a defensive line most go-wide payoffs lack: hold it up on an opponent's combat, drop it after they commit attackers, and any creatures you flashed in to block that turn get double strike right along with it, so your blockers bite back for twice. What you swing with is nearly beside the point; you are paying for a portable double-strike anthem priced to sit uncast until your board multiplies. Its job is to convert one big commitment into a lethal alpha strike from whatever can already swing, which means it rewards hoarding over developing, then dumping everything on the one turn it counts. Build the swarm, then flash in the reason the swarm kills.