Hverhuldra

The hverhuldra can breathe air and water.

The hverhuldra’s innate spellcasting ability is Charisma (spell save DC 14). It can innately cast the following spells, requiring no components:
At will: create or destroy water, detect poison and disease, purify food and drink
1/day each: blindness/deafness, protection from poison

If the hverhuldra sits in a body of slow-flowing or standing water, such as a hot spring or a small creek, for at least 1 hour, the water becomes purified and rendered free of poison and disease. In slow-flowing water, this purification fades 1 hour after the hverhuldra leaves the water. In standing water, this purification lasts until a contaminant enters the water while the hverhuldra isn’t in it.

As a bonus action, the hverhuldra gives one willing creature within 60 feet of it the ability to breathe water for 1 minute.

While the hverhuldra submerged in water, it has advantage on Dexterity (Stealth) checks, and it has resistance to bludgeoning, piercing, and slashing damage from nonmagical attacks. If it takes cold damage, this trait doesn’t function until the end of its next turn.

The hverhuldra makes two steaming fist attacks.

The hverhuldra spits scalding water in a 30-foot line that is 5 feet wide. Each creature in that line must make a DC 15 Dexterity saving throw. On a failed save, the target takes 21 (6d6) fire damage and is blinded for 1 minute. On a successful save, the target takes half the damage and isn't blinded. A blinded creature can make a DC 15 Constitution saving throw at the end of each of its turns, ending the effect on itself on a success.

Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) bludgeoning damage plus 7 (2d6) fire damage.

When the hverhuldra takes cold damage, it uses the steam from the impact of the cold on its body to magically create a cloud of steam centered on a point it can see within 60 feet of it. This cloud works like the fog cloud spell, except the hverhuldra can dismiss it as a bonus action.