Eternal Thirst

Most lifelink auras stop at the keyword: tack on the lifegain, maybe a small stat boost, call it a combat enabler. This one bundles lifelink with a growth engine keyed to attrition, and the pairing is what makes it more than a buff. The lifelink alone turns the enchanted creature into a clock that races your life total upward; the counter trigger rewards you for grinding through the opponent's board, so the longer a board stall lasts, the larger and more unkillable your threat becomes. The two halves reinforce each other: as the creature grows from opposing deaths, each swing gains you proportionally more life, compounding the cushion that lets it keep attacking. The design tension is the usual aura problem, since enchanting a creature invites a two-for-one if it gets removed in response, and here the downside is steeper because the counters and lifegain only accrue while the host survives. The trigger also wants a board where opposing creatures are actually dying, which points it toward a deck built to trade and remove rather than one racing for a quick kill. That alignment, an effect that pays off the same grinding plan it demands you play into, is what separates it from the generic +2/+2-with-upside auras it superficially resembles.