Chitin was probably present in the exoskeletons of Cambrian arthropods such as trilobites. Fish bones and the hard exoskeletons of crustaceans or insects are regurgitated as pellets. Others have hard exoskeletons, outer shells like those of insects and crustaceans. Insects have segmented bodies supported by exoskeletons, the hard outer covering made mostly of chitin. Stony corals secrete massive calcium carbonate exoskeletons. Some encrusting bryozoan colonies with mineralized exoskeletons look very like small corals. In invertebrates with hard exoskeletons, various mouthparts may be involved in feeding behaviour. Scarabs are much more powerful than Drones, equipped with heavily armored exoskeletons and powerful weaponry. Weta Workshop made the film's spacesuits, exoskeletons and weaponry. In species with calcareous exoskeletons, these do not mineralize until the zooids are fully grown. Insects have spiracles on their exoskeletons to allow air to enter the trachea. It has strong jaws with which it bites through the exoskeletons of rainforest insects. They soon shed their membranes and their exoskeletons harden. The insect exoskeletons and soil are not digested, being ejected in the waste. The teeth are a series of sharp points to poke holes in insect exoskeletons.