What kind of insect larva?

Occasionally I notice worm-like larvae climbing up the interior walls of my house. They look like maggots, but surrounded by a cocoon of debris that they seem to pick up off the floor (cat hair, dust, etc.). They stick their heads out to climb but otherwise remain in the cocoon. The cocoons are about half an inch long.

I took some pictures of one but it says under posting rules that I’m not allowed to post attachments. Anybody know what these things turn into when they grow up?

Plaster bagworms, aka household casebearerPhereoeca uterella.

Video

Yeah that’s the one. Thanks.

OK, one more question. Apologies if I’m mistaken here, but from what I’ve read moths of this and related genuses tend to feed on bio-polymers like silk and keratin.

The question is, what’s the likelihood that these critters are subsisting on shed pet hair? The wife and I keep the cobwebs at bay, but the animal hair is constantly replenished, especially this time of year.