This hideous humanoid creature has slimy, transparent skin; webbed, humanoid hands; and a snaggletoothed, horse-like face.
A kelpie is a deadly shapechanging predator that, in its natural form, appears as a hideous combination of emaciated horse and sickly humanoid, with slimy, transparent skin and long, stringy hair. Its face is long and equine, with a mouth filled with jagged teeth. Few, however, ever see a kelpie in its true form, for kelpies almost always encounter other creatures while in disguise as a humanoid, horse, or hippocampus, reverting to their true form only after their targets have drowned so that they can feast on their victims, leaving behind only the heart and liver (as both of these organs are distasteful to most kelpies). Kelpies can be found in saltwater and freshwater environments, including fens, rivers, swamps, and underground pools and lakes. Communities living near kelpie lairs believe that folk who die on the water or are killed by a kelpie become kelpies themselves. Kelpies may serve as steeds for aquatic fey or other water monsters while in their hippocampus forms, sometimes without their riders ever knowing the truth of the steed's sinister nature. A typical kelpie is 6 feet tall and weighs 170 pounds.
In their true form, kelpies are indistinguishable from normal seaweed. They are found in saltwater and freshwater, swamps, fens, and stagnated underground pools and lakes. Sages and scholars believe the kelpies were created by an evil water elemental goddess. In her human guise, a kelpie appears as a beautiful female with long flowing dark hair, emerald eyes, and soft, pale skin. She is cloaked in robes of seaweed or wears nothing at all. A kelpie often assumes a semi-human form in which her lower torso is composed entirely of seaweed. Kelpies lie in wait for their foes, and when a target moves within range, they reshape their form to appear human (in most cases, they take the form of a drowning woman) so as to lure the target closer. If the ruse is not detected and the opponent moves within 5 feet of the kelpie, she attacks, attempting to charm and drown her victim. Drowned foes are taken back to the kelpie's lair and devoured.