Babies transform into adults
In some animal groups, growth does not take place as a long, gradual process, but rather in a series of highly separate stages. In the most extreme cases, there are four stages, and none of them are very much alike. The classic example is a butterfly, which goes from larva to colourful flier, but other insects also go through a similar process known as complete transformation of metamorphosis. Other species transform, but not completely.