Basilisk Collar

The two-keyword pairing is the entire trick, and it is multiplicative rather than additive. Deathtouch turns any nonzero damage into lethal removal; lifelink turns that same damage into life gained. Strap the collar onto something that deals damage at range or in volume, and each keyword amplifies the other into a different category of card. A pinger with a built-in damage ability becomes a repeatable creature-killing machine that gains life every time it fires. A creature that splits damage across multiple targets, or hits a player and a creature in one shot, drains and removes in the same beat. That is the design seam the card lives in: it does almost nothing strapped to a vanilla beater (deathtouch on an attacker is marginal, lifelink merely incremental), but it converts any source of flexible, repeatable, aimable damage into a board-control and life-buffer engine at once. The equip cost is the only governor, and it is deliberately light: cheap enough to recur, cheap enough to suit up a fresh body once the old one has done its work, though only ever at sorcery speed and never in the middle of a combat exchange. What makes the collar endure is that it does not care what color or kind of damage it amplifies, only that the damage exists and can be pointed somewhere useful. It is a payoff that arrives years before its enablers do, waiting for whatever damage-dealing engine the next set happens to print.