lookingfrank said: People will get killed after their shirikodama are ripped off, no?
Hard to say with fictitious organs. I'm wondering, what would be the nearest organ that roughly fits the description of a shirikodama? Spleen? Gallbladder?
The shirokodama is never really explained definitively, and in some instances of the myths, it's just plain your intestines, in some instances, sucked out through your belly button. In other instances, it's your soul, period.
I'm fairly sure that ZUN is just leaving it unstated because that way, imagination can make it... "funnier" isn't quite the right word, but you get the idea.