Sootballs (Susuwatari in Japanese) are species that appear in the films My Neighbor Totoro and Spirited Away. They are small round balls made from soot that dwell in old and abandoned houses and leave black dirt in their wake. If the house becomes inhabited, they decide if the inhabitants are nice people, if they are, they will leave.
In Spirited Away, they work in the bathhouse in return for small star shaped food. They carry coal to help power the bathhouse.
- Susuwatari - at Wikipedia