Very shivery! I can see Men hearing bits of First Age lore and song and tale and stitching bits together to get this. 

 Oh gosh, this made me think that poor Fingolfin can't be re-embodied without his head, so he haunts the Lands Under Wave. Although admittedly that doesn't really fit with how Mandos etc. works, but then I read Lferion's thought that it's a Mannish legend, and it all made sense — they really don't quite understand how re-embodiment works. (And have some grizzly ideas about it!)

I love how spooky this is, followed by the tonal shift in the last line 😁. It's great. As Lferion suggested, I can totally imagine an old Edainic grandparent telling this strange tale to their grandchildren, making them chuckle with surprise at the end. 

Oh yikes. Fingolfin eternally on Rochallor searching for his head. A very frightening (and tragic) image. 

Ooh fantastic, a little chilling but also very much grabs the imagination! 

It does have the feeling of a real folk tale!

I suppose it fits that it would be about Fingolfin that such a tale arises.