Pusa

Pusa are creatures with two forms; their human form, and their monster form. Their monster forms vary quite a lot, but mostly share traits of seals, cetaceans, otters, marsupials and something dog-like.

Pusa historically lived in large pods within bodies of water, but these pods have, for the most part, dissolved as humans encroach on marine environments. Ocean pusa pods still exist, though they are rare and hidden away.

More to be added...

Becoming a pusa
A pusa may take in an injured or weakened human who comes near their inhabited body of water and turn them into a pusa with special magic. The human's first transformation into their pusa form happens involuntarily a week after being turned.

Transformations
They transform into their monster form at night,