Cocoon/kəˈkuːn/ Definition 1 of 3Pro Tip 1/3Metamorphosis Stage A cocoon is specifically for the transformation phase of insects, not any shelter. The silk moth's cocoon houses it during metamorphosis. Pro Tip 2/3Natural Material Cocoons are made from materials the insect produces, like silk or other substances. Many cocoons are silky, but some may use leaves or twigs. Pro Tip 3/3Temporary Shelter Cocoons are a temporary structure, the insect leaves it once mature. After the transformation, the butterfly leaves its cocoon behind.