Brine Hag

Amphibious. The hag can breathe air and water.

Brine Walk. The hag can move across bodies of salt water with its walking speed, and ignores rough terrain or other threats imposed by these surfaces.

Return to Worms. When the hag is reduced to 0 hit points, they breaks apart into a plaresh demon (see the Creature Codex pg. 89) in the same space. The creature can reassume their hag form after one hour by using their Infest Corpse ability.

Innate Spellcasting. The hag’s innate spellcasting ability is Charisma (spell save DC 14, +6 to hit with spell attacks). They can innately cast the following spells, requiring no material components:

At will: hold person, infestation (2d6)

3/day each: cloudkill, blight, disintegrate

1/day each: antipathy/sympathy

Multiattack. The hag makes two Claw or Hagfish attacks.

Claw. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 10 (2d8 + 1) piercing damage plus 18 (4d8) poison damage.

Hagfish. Ranged Spell Attack: +6 to hit, range 60 ft., one target. Hit: 30 (6d8 + 3) poison damage, and the target must make a DC 15 Dexterity saving throw. On a failure, the thrown hagfish latches onto their skin and begins devour them, dealing 1d8 poison damage at the end of each of the creature's turns. The creature may repeat this saving throw at the beginning of their turn to try to remove the hagfish.

Illusory Appearance. The hag covers themself and anything they are wearing or carrying with a magical illusion that makes them look like an ugly creature of their general size and shape. The effect ends if the hag takes a bonus action to end it or if they die.

The changes wrought by this effect fail to hold up to physical inspection. For example, the hag could appear to have normal human skin, but someone touching their hand might feel the slimy wriggling of their true form. Otherwise, a creature must take an action to visually inspect the illusion and succeed on a DC 16 Intelligence (Investigation) check to discern that the hag is disguised.

Horrific Feast. The hag feeds on the corpse of one enemy within reach that died within the past minute. Each creature of the hag’s choice that is within 60 feet and able to see the feeding must succeed on a DC 15 Wisdom saving throw or be frightened of the hag for 1 minute. While frightened in this way, a creature is incapacitated, can’t understand what others say, can’t read, and speaks only in gibberish. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the hag’s Horrific Feast for the next 24 hours.