Phereoeca uterella (Household Casebearer or Plaster Bagworm)

Typically found indoors in humid climates, often in garages, closets, and underneath furniture. They prefer dark, undisturbed areas with high humidity.

Larvae feed on spider webs, old silk casings, wool, lint, hair, and other keratin-containing materials or detritus.

The larva constructs a protective, flattened, pumpkin-seed-shaped case out of silk and environmental debris (dust, sand, fiber). It carries this case around and can retract inside when threatened. It eventually pupates inside the case to become a small moth.

Generally harmless to humans (does not bite or sting). Can be a minor pest if they damage wool or fabrics, but usually feed on debris. Their presence often indicates high humidity or dusty conditions.