The hickory tussock moth caterpillar has a neat protective mechanism --its "hairs" have a toxic chemical on them that, depending on the source, is called venomous or poisonous. There is a lot of contention about what the particular term should be. But, in short, if you touch this caterpillar, its hairs can cause your skin to become irritated (and depending on your sensitivity, you could develop a rash or an allergic reaction).
I painted a watercolor portrait of one the last time I came across a hickory tussock moth caterpillar, but since then, I haven't encountered one in several years. That is, until we discovered this particular specimen.
After being photographed it was released back into nature!
Location: Dexter, Michigan.