Hailey wakes up in the middle of the night, her scales feeling like they're on fire. They itch like crazy, but by now she knows how to soothe them: a dip in the water. She rushes towards the Lagoon, completely unaware of the spell wrapped around her, leading her to the water.
An exhale of relief comes from Hailey, her new scales feeling perfectly at home in the water. They grow past her arms, crawling all the way up to her face, giving Hailey a fine tropical fish coat of scales. Her hair even lightens slightly to match. Her tail starts to grow further and further out, while her feet become shorter and shorter, until her legs are nothing but nubs under her stomach. Their muscle and bones have been converted to help the growth of her new elegant tail.