This is a moth larva, a small white bag with a dark brown head inside. Adults are light yellow insects and are afraid of light. If crushed to death, it will give off an unpleasant smell. Larvae feed on wool, hair, fur and feathers, and move slowly. It will destroy textiles and endanger animal specimens in libraries or museums. Adults don't feed

Regularly sorting out sundries and keeping the environment clean can reduce the occurrence of harmful insects.