Huh, so they do. That might give them some kind of variety, like different keys for each floating keychain.

[Because of course they float, if they're ghosts or not.]

Oooh, or maybe they steal your soul and locks it away with one of their keys. And to get it back, you must pick the correct key!

[Don't sound so excited by that, Atsuro. You're a former victim of a ghost, remember?]