Bagworms

Bagworms, bagmoths, or bagworm moths are a small, cosmopolitan family of moths which are so-named for the habit of their caterpillar form to build small, protective cases to hide in made out of silk and environmental materials on-hand such as sand, soil, lichen, or plant materials. They remain mobile until the pupa stage, when they attach to rocks, trees, or fences. They also attach themselves when at rest.

They can easily be confused for case-bearer moths, but female case-bearers metamorphose into full-grown adults, whereas bagworm females remain in a larval-like neotenous stage throughout life.

They are most commonly seen in Japanese media sources, although they are rarely pointed out as specifically being bagworms, with the identification as such being left to educated fan bases.