About 4 inches long, green like a tomato hornworm, but weirdly fuzzy. Photo shows correct color and features, I hope. Back end had strange gold and tan protuberances. At least, I think it’s the back. (Conshohocken, PA USA)
the photo is of the Imperial moth caterpillar.
These are found in eastern US, Ontario and Quebec.
This is one of the silkmoth (Saturniidae family) caterpillars…most get very large … rather spectacular in color and size!
This caterpillar feeds on leaves of Bald Cypress, basswood, birch, cedar, elm, hickory, Honeylocust, maple, oak, pine, Sassafras, Sweetgum, sycamore, walnut.
Adult moths do not feed and do come to lights at night.