Ring of Anchoring (Patreon)

Ring, rare (requires attunement)

While attuned to this ring, you can breathe normally underwater, and whenever you’re pushed against your will, the distance you’re moved is reduced by 10 feet.

Curse. Once you attune to and wear this hammered lead ring, the arm that’s wearing it becomes unbearably heavy when it’s submerged underwater. When underwater, make a DC 20 Strength (Athletics) check. On a failure, you’re dragged downward 30 feet at the start of each of your turns, and your movement speed becomes 0. You can reattempt this saving throw every minute. On a success, you can move your arm, albeit sluggishly, for 1 minute. While you can move your arm, your movement speed is halved, any attack roll you make with the arm is made with disadvantage, and any Strength or Dexterity check you make is made with disadvantage. If you’re still underwater at the end of this minute, you’re forced to reattempt the saving throw. You can’t remove this ring once you’re cursed by it, and you remain cursed until you’re targeted by the remove curse spell or similar magic. You can remove the ring and the curse without magic by physically removing the finger that’s wearing it. Once removed from the water, your arm’s weight and your movement speed return to normal.

"I've heard it called the merfolk's wedding ring."