WTH is this that just fell out of my /6?!

I'll just take the valve cover off before starting it up to see if there's anything else in there. I never saw any spring, and there wasn't anything on the outside of the PCV valve, so I assume you mean something else from inside the valve? Either way, better safe than sorry.

Yes spring is inside the pcv body, outside the pintle. Very light spring, could have rusted away.