Animal juvenile form that is converted to an adult form via a process known as metamorphosis.

Metamorphosis is seen in numerous animals including tunicates, various fish, certain amphibians, and numerous non-chordate invertebrates.

In insects, metaphorphasis can be complete or, instead, incomplete. The latter, however, do not display a larval form but instead are known as juveniles as nymphs.

The larvae of frogs are called tadpoles. In butterflies the larval form is known as caterpillars. In tunicates the larval form resembles a lancelet. In sponges the larval form may represent the evolutionary precursor to eumetazoan animals generally.