On a cultural note, it's not that uncommon for real-world japanese shrines to keep the mummified remains of supposed kappa as relics.
That's true.Like that thing?But strange things get offered every once in a while, too.Youkai don't usually leave corpses.They just disappear if you beat them.And what's the point in offering something like this to a shrine?...is it?"The Kappa's Arm"...