The worm lives inside a smooth tube of fine mud or sand particles held together with mucus.

Sand filters are bulky, heavy, have some spill over of sand particles and require chemicals to enhance water quality.

Telekinetic beings can take control of her sand particles.

On its passage over the desert, it picks up fine dust and sand particles (between 0.5 and 10 micrometres).

This small particle size means that mud particles tend to stick together, whereas sand particles do not.