Some Caddisfly larvae create quite amazing cases in which they hide. These cases, always in water, either permanent or temporary, swift-flowing or slow, all depending on the species of caddisfly, can be as simple as a hollow stem, or as elaborate as a tube created with all manner of debris. Some caddisfly larvae spin webs underwater to catch food, while still others are free-roaming, not restricted to cases or webs. Food can consist of plant debris or other creatures.