I've heard stories of people re-micing a voice or instrument with certain keys of the piano open so the strings sympathetically vibrate with the sound, thus adding more harmonics and another timbre to the sound.
Has anyone else tried something like this in designing a sound? Would it work well to reinforce a creature vocal or creepy pad or synth with? I'm curious if anyone else has thought of this or done this in the past before I give it a go.