Zeaweed

Seaweed Wrack, AKA Zeaweed, is an Equestrian kelpie from the Maricolous Coasts. She is of the impure variant which, unlike pure kelpies like Cassie or Youth Lagoon who live in both freshwater or seawater environments due to harnessing Equestrian magic, are poor creatures who subsist only on seaweed, and are known sea hags that haunt the beaches around their homes, turning into sea foam when dying. Wrack had been a poor abandoned orphan who lived in a cursed kelp forest around her home as a wild selkie and ended up missing for a year until returning as a monster of pure seaweed, being assimilated by what's called a Knucker, a literal leafy sea dragon and sworn guardians of kelp forests, the healthiest ecosystems in the ocean. This Knucker was a rogue guardian that turned Wrack evil with goal of punishing all seaweed-eaters including seaponies, keeping the Knucker as a pet not knowing it's the true evil.