Surestrike Trident

Most equipment exists to make a creature bigger or harder to kill; this one exists to turn it into a single-use cannon. First strike is the baseline gift, but the payoff is the tap-and-detach activation that converts the equipped creature's power into one burst of damage aimed at a player or planeswalker. The catch is the tap. A creature swinging in is already tapped when blockers come down, so the cannon does not fire mid-combat unless the wielder has vigilance or simply holds the body back: this is a precombat or off-turn play, a deliberate "stop attacking and fling the face" decision rather than a combat trick. Each firing strips both the first strike and the weapon, and re-arming costs four mana all over again, so the equip economics punish repeat use hard (the creature survives every time; you are paying to bolt the trident back on, not to replace a sacrificed body). The targeting restriction (player or planeswalker, never a creature) keeps the rate from doubling as removal; this is a clock-accelerant, not an answer. The whole thing scales with a stat the equipment does nothing to grow, which is the awkward part of the design: the bigger the body you attach it to, the better the burst, yet the trident contributes none of that size itself. It reads as an early experiment in giving equipment a job beyond stat-padding, and the answer it landed on never settled comfortably outside dedicated big-creature shells.