Sea Spawn
Sea spawn are the result of humanoids that become lost at sea or live near its shores and transformed by powerful creatures that live there. This transformation makes the sea spawn enthralled to their creator, and are unable to leave the ocean for more than a day.
Sea spawn superficially resemble their previous humanoid form, but are warped with oceanic traits, such as fins and gills, or growths of coral and barnacles. Their forms may include elements of other sea creatures, such as having tentacles, shark mouths, or sea urchin spines. Sea spawn can have any combination of such forms.
The ones living on the shores of Lake Evendim had the ability to disguise themselves as normal looking people until the enchantment was broken when frightened or fighting.