Aequor Rune

This round piece of labradorite is roughly 4 inches in diameter and 1 inch thick in the middle, but tapers to a point around the edges. The Aequor Rune that is carved into this rock is only visible when the light shines on it the right way. 

 The rune has charges equal to your level for the following properties. The rune regains all expended charges when you finish a long rest.

You can only use a number of charges equal to your proficiency bonus in one turn. 

While attuned to this rune, you have a swimming speed equal to your walking speed, and you can breathe underwater.

Desiccate (1–6 charges). As an action, choose one creature you can see within 60 feet of you. The target must make a Constitution saving throw, taking 1d10 necrotic damage per charge spent on this ability, or half as much damage on a successful one. You can then use your action on your next turn to regain hp equal to 1/2 the damage dealt (minimum of 1).

Watery Grasp (2 charges). As an action, you unleash a wave that surges forth and then retreats to you like the rising tide. You create a wave in a 20-foot-by-20-foot square. At least some portion of the square’s border must be within 5 feet of you. Any creature in that square must make a Strength saving throw. On a failed save, a target takes 2d6 bludgeoning damage, is knocked prone, and is pulled up to 10 feet closer to you. On a successful save, a target takes half as much damage. You can increase this ability’s damage by 1d6 per additional charge spent on it.

Water Whip (3 charges). As an action, you unleash a jet of water in a line that is 60 feet long and 5 feet wide. Each creature in the line must make a Strength saving throw, taking 3d6 bludgeoning damage on a failed save, or half as much damage on a successful one. In addition, you can move each target that fails its saving throw to any unoccupied space touching the line. You can increase this ability’s damage by 1d6 per additional charge spent on it.

Water Breathing (4 charges). As an action, you grant yourself and up to ten willing creatures you can see within 60 feet of you the ability to breathe underwater for the next 24 hours.

Call of the Ocean (5 charges). You conjure up a wave of water that crashes down on an area within range. The area can be up to 30 feet long, up to 10 feet wide, and up to 10 feet tall. Each creature in that area must make a Dexterity saving throw. On a failed save, a creature takes 5d8 bludgeoning damage and is knocked prone. On a successful save, a creature takes half as much damage and isn’t knocked prone. The water then spreads out across the ground in all directions, extinguishing unprotected flames in its area and within 30 feet of it, and then it vanishes. You can increase this ability’s damage by 1d6 per additional charge spent on it.

Water Sphere (6 charges; conc., 1 min.). As an action, you cause a sphere of water to form around a creature. Choose one creature you can see within 60 feet of you. The target must make a Dexterity saving throw. On a failed save, it becomes trapped in the sphere of water until your concentration ends. While the target is trapped, its speed is halved, it suffers disadvantage on attack rolls, and it can’t see anything more than 10 feet away from it. However, attack rolls against it also suffer disadvantage. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a successful save, and if they fail the save, they take 1d6 bludgeoning damage.