The Selkie is a Scottish creature that takes the appearance of a seal and when it removes it's skin it turns into a woman. If a selkies skin is stolen then it must remain as a human.
The Kelpie is also Scottish, it takes the appearance of a white horse which entices you to ride it, when you so, you cannot let go of it and the Kelpie will jump into a lake and drown you.
I think a Kelpie is only in Scotland, since it lives in Loch Ness. However, Some people believe in Nessie, some don't. In 1933 a "photograph" was taken, but ended up being a hoax.
You can read more about Nessie on Wikipedia https://en.m.wikipedia.org/wiki/Loch_Ness_Monster it's really interesting.
I'm also Scottish, my great great grandfather owned land in Scotland, before fleeing to America, I don't know the full story, but I do know my coat of arms, my badge which says I shine, not burn in Latin, and the piece of land.
Another Scottish mythical creature is called a Brownie, theyre household spirits similar to a hobgoblin, they do house hold work usually at night when you're asleep. (Similar to the elves who helped the Cobbler fix shoes)
About spiritual, there are Many, Many types of water creatures. I know of Mermaids and the monster of Loch Ness. I do not know if Loch Ness monster exists, but Mermaids exist and many of them are male as well.