Seth Brundle undergoes eight specific stages in his horrific metamorphosis into Brundlefly. At first just after Seth Brundle merges with the housefly, he appears as a completely normal human. Gradually he begins to develop lesions on his body that sprout large thick insect-like hairs, as well as boil-like growths on his face. Brundle's teeth and fingernails also begin to fall out in this stage.