Household casebearer (plaster bagworm)

Indoors in warm, humid, quiet areas such as bathrooms, closets, ceilings, and beneath furniture; also found on sheltered exterior walls.

The larva feeds mainly on cobweb debris, dead insects, hair, lint, and other keratin-containing organic material, rather than stored food or living fabric.

The caterpillar lives inside a portable, spindle-shaped case and moves slowly while grazing on debris; it pupates within the case and adults are small, silvery-gray moths attracted to light.

It is harmless to people, pets, and structures and rarely causes meaningful damage. It helps recycle organic debris, though noticeable numbers indicate accumulated lint, dust, or humidity.