Bone Fiddle

You rub your middle finger across your thumb like a bow
against a fiddle while simultaneously humming a discordant
tune under your breath. Nearby, you see a translucent bone-
white fiddle bow appear and sink into the flesh of your target.
It begins sawing, as if playing your target like a fiddle.
Each round on its turn, the victim must make a Charisma
save or take 4d8 points of slashing damage and disadvantage
on stealth checks. A successful save negates the damage and
ends the spell The spell's effects continue even if the subject
moves so that you no longer have line of sight.
This spell can not effect creatures that do not have a hard
surface for the fiddle to play (such as oozes or ghosts)