Giant Leopard Moth caterpillar
This is the same Crazy Caterpillar when it was curled up in a ball. The red stripes are a form of protective coloration if the stiff, black hairs don't deter a predator. It will turn into a white moth with black spots. I get a lot of requests for identification of this caterpillar in the fall!
(keywords: black hairy caterpillar with red stripes)