ABYSTERATA

Appearance & Physiology
Abysterata are deep-sea relatives of mewmaids, adapted to the cold and darkness of their abyssal habitat. They have sharp teeth with long fangs, fin "ears", two or more pairs of roughly arm-length fins on their sides, and large claw hands. Despite usually living in deep waters, they can also survive in shallower areas.
Similar to mystimews and mewmaids, their physical form is very flexible. Like mewmaids, abysterata can change into a land form to come out of the water. In this form, their side fins disappear and they gain legs instead. Their eyes, adapted for the deep sea, usually appear narrower on land. In their land forms, abysterata are on average 7'2'' / 2.2m (their aquatic forms are the same in scale).
An important feature of abysterata is their tendency towards mutations; almost every abystera will have at least one mutation. Some of the most common mutations include (but aren't limited to) spines, multiplied body parts, longer teeth, pieces of exoskeleton, and bioluminescence.
Magic Ability
Despite their close relation to mystimews and mewmaids, abysterata are not as adept at magic, though they have an inherent ability to use kinetic (for movement in water, especially with non-hydrodynamic mutations) and transformative (for form switching) magic.
Life / Society
Abysterata are solitary creatures, especially when it comes to other species, who they may seem monstrous to.