Maggot

A maggot is the common name of the larval phase of development in insects of the order Diptera (flies). Sometimes, the word is used to describe the larval stage of any insect.
Parasitic Maggots.
While large maggots only eat necrotic tissue in living animals and can be symbiotic, certain types of maggots are parasitic, like the Botfly larvae. These larvae spend part of their life cycle as parasites under the skin of living animals. As a result myiasis will take place in the host causing symptoms like sores and irritating lesions and even death.