Break it if you have to. A grommet goes into the valve cover, then the PCV valve. If you can carefully cut away some of the grommet at the base, then it should come out fairly easily. Or try some penetrant. The foaming kind works best.
Its smog equipment. His might be bad. I've always been told if you shape them and they make noise they're useable, but if they don't make noise they're bad. Kinda bassackwards, but supposedly thats it. If not, mine is broken.
Positive Crankcase Ventilation Valve. Basically a check valve for your emissions. It allows excess fumes to be filtered through your air intake system.