This gnarly looking fellow was on the tip of a goldenrod leaf, waiting for unsuspecting prey to land. When one does, this bug will immediately seize it. They are designed to suck out the bodily juices rather than eating the prey whole. You may frequently find the bodies of other insects dangling from plants, evidence that they have been the prey of this bug, or just as often, perhaps a crab spider, which does much the same thing as the ambush bug.