Spirit Link
Lifelink-on-a-bottle, printed years before lifelink existed as a keyword. The design solves a specific problem: how does white answer a beater it cannot easily kill but whose attacks it needs to stop losing the race to? The Aura frame is the discipline. You pay a card and a mana, the opponent's threat keeps swinging, and every hit nets to zero on your life total instead of widening the gap, because the damage you take is matched by the life you gain. The key detail is that the trigger keys off any damage the enchanted creature deals, combat or otherwise, which is what gave it a second life as a combo piece: strap it to anything with a damage-based tap ability (Prodigal Sorcerer being the canonical early target, later the various pingers) and the lifegain becomes an engine rather than a stabilizer.
The lifelink keyword introduced later folded the racing instinct into a single word, but it folded it onto the creatures that have it: lifelink rewards the creature's controller, so it can never reproduce what Spirit Link does, which is route an opponent's damage back to you. The Aura puts the lifegain on the caster regardless of who owns the body, and that is precisely the function the keyword leaves untouched, both the defensive use against an enemy beater and the combo use on a borrowed pinger. The card is a useful artifact from before keywords had been extracted from their Auras, and the seam still shows.
