Cassie

Cassie was a Kelpie and a member of Cassie Kelpie and the Water Sprites, a musical group.

History
Cassie was a good friend to the Water Sprites, a group of small, aquatic equine-like creatures. Being a kelpie, Cassie had hypnotic powers in her singing and used her powers to hypnotize all of to destroy a dam to save the water sprites from getting sick, would would flood the entire town. The various pets of the Mane Six, lead by managed to save the residents of Ponyville from her spell and after they came to their senses, they helped Cassie get the Water Sprites across the dam.

Personality
Cassie cared deeply for her friends, but didn't appear to think much of people she wasn't friends with, using them as slaves to hep her and the Water Sprites.

Abilities

 * Hypnotism: Cassie has the ability of hypnotism and can hypnotize people with her songs.

Behind the scenes
Cassie was the first kelpie to appear in the series, with more appearing in Season 10.