I am curious what animal is this. It is/lives inside some kind of cocoon, about 1 cm in length. They are attached to walls and to the ceiling, but sometimes they fall off. Inside the structure there is a small worm that can come out at both ends alternatingly. It can then hold on to the ground to move the cocoon around. They are said to feed on paper.
This little dude is not a Caddisfly, but a true moth, Tinea pellionella, a case making clothing moth. Confusing because they do resemble caddisfly larvae cocoons more so than those of their own family (Tineidae). Sort blurb Here:
"The brown-headed larva spins a silken case that is open at both ends. The case in the above image is covered with fine sand and debris, and superficially resembles a caddisfly case. The flattened case is about 10-11 mm long (3/8 to 1/2 inch). When crawling, the larva's head, thorax, and three pairs of legs protrude out of the case, and drag it along. According to Internet sources, the larva feeds on a variety of material, including hair, fur, silk, felt, feathers, woolen clothing, upholstered furniture and carpets. It apparently prefers darkness and soiled clothing, and is not fond of synthetic fabrics, such as nylon and polyesters."
This is probably caterpillar of one of the moth species from family Psychidae. They larvae looks like Trichoptera larvae and builds similar cases out of silk and material found in nearby surroundings. In contrast to Trichoptera, Psychidae caterpillars don't live in water, and some of them inhabit stones and walls, where they feed on lichens.
This is a wild stab in the dark, so downvote me as you see fit: Caddis fly larvae (Insect Order Trichoptera). I thought caddis larvae were aquatic though.
