Tam Lin
Here’s Anais Mitchell and Jefferson Hamer performing their version of a traditional British ballad about a shape-shifter:
They aren’t the first modern folk artists to have a go at this:
These are both versions of Child Ballad #39.
See also Benjamin Zephaniah and Peter Gabriel’s version.
There are in fact hundreds of versions of the tale. Feel free to share your favorite in the comments; perhaps you can explain to me why the story has such lasting appeal.