
Polyphemus Moth
The adult flaps its wings exposing eyespots on the wings when it feels threatened. This makes the moth look like a bigger animal, deterring possible predators away.
Polyphemus caterpillars are a bright green color with a brown head and legs. When threatened the caterpillar will make clicking sounds with its mandible to warn off any predators. Sometimes after clicking they will regurgitate unpalatable fluids.
https://entnemdept.ufl.edu/creatures/MISC/MOTHS/polyphemus_moth.htm

Top photo: NPS | J. P
Bottom photo: Azucena Ponce/USFWS