Another "What is this?" Question
 

So on lowering the engine out of the Boxster, this little green bell shaped item fell out and hit the floor. It appears to be a well cooked rubber seal for something.
What is this? Part of the muffler bearing? Perhaps from the tail light fluid level sensor?

Maybe something kicked up onto the engine from the road?

Has anybody seen this before / know what it is? Something important?

http://986forum.com/forums/uploads01...1385236589.jpg

Any thoughts would be appreciated.