Mage Slayer

The trick here is that the equipped creature's attack trigger ignores blockers entirely: the combat damage step is now a sideshow. Whatever the creature's power is, the player or planeswalker being attacked takes it as the attack trigger resolves, before blocks, before any chump-block math, before the defender gets to decide what trades. This is a Trample that does not care about toughness, a burn spell that scales with the body it sits on, and it stacks on top of whatever the creature does in combat afterward. The interesting consequence is that it collapses two questions defenders usually get to ask (do I block, and what do I block with) into one they cannot answer: the trigger is already on the stack as a triggered ability, so a creature that gets blocked and killed still landed its full power upstairs. Pair it with anything that pumps power at instant speed and you have effectively doubled it: the attack trigger reads the boosted number, and the combat damage reads it again. The equip cost is the friction, steep enough that the Equipment wants to find a single large, hard-to-remove body and stay attached rather than shuttling between attackers. It rewards going tall and going fast: the bigger the creature, the more the blocker becomes irrelevant.