Hickory Horned Devils are an INCREDIBLE type of caterpillar found in the Southeastern US. They most spend most of their larval stage high in hickory and related trees, munching on bark and leaves. Due to this, they aren't usually seen until late summer and early fall, when they leave the trees to make a burrow and metamorphose during the winter. When mature, they become the HUGE Imperial Moth, which can get even bigger than the caterpillar.
Male Adult
If anyone can find a picture of a female, it would be appreciated.
Video I made with a Hickory Horned Devil in it
YouTube - Teen Wilderness Episode 2