Bagworm moth case (likely plaster bagworm)

Quiet, humid indoor areas and sheltered exterior walls, especially masonry, garages, and buildings with spider webs or accumulated lint.

The caterpillar feeds on wool, hair, feathers, dead insects, spiderwebs, and other keratin-rich organic debris; adults generally do not feed.

The larva lives inside a portable silk-and-debris case, extending its head and legs to crawl and feed. It pupates within the case, often attached to a wall or crevice; adults are small, grayish moths.

Usually harmless to people and pets, but infestations can damage woolens, furs, feathers, and other animal-fiber materials. It helps recycle organic debris, though indoors it may indicate dampness or poor cleaning.