Have you heard of the story of the Stomach and the Limbs? Where the limbs refused to work because "why should we feed something that doesn't work aside from eating?" And then the stomach wasted away with the limbs until they realised that the stomach gave them energy to function and decided to feed it.

That story had me thinking that the owner of the body had become depressed, hence them not moving or eating anymore and that one day someone helped them and they got better and began to function again.