There is an invisible dagger-wielding dwarf running rampant on Chicagoland streets who seems to be waiting in the bushes for cyclists to crash. One got me two weeks ago when I broke my arm after falling off my bike on the way home from work. I didn't get a good look at him, as he was invisible, but based on Wait, Wait... Don't Tell Me host Peter Sagal's description of him, I'm betting we got jabbed by the same bastard.