Do you have any of this in your yard?? This is a terrible plant, discovered in a Lake Forest, Illinois yard. It's called "Hogweed", a relative to carrot and Queen Anne's Lace. If you get any of it's sap on your skin, it will blister and fester, once exposed to the sun. The effects are called phototoxic and it would, at the very least, turn a good day into a bad one!
Just another example of exotic invasives being exotic and invasive....ugh