Unknown black shiney sphere?

Unknown black shiney sphere?

Observation - Unknown black shiney sphere? - UK and Ireland. Description: I have seen these several times. This one was discovered under some old black polythene beside a sheep feeder, in rough hilly pasture. Can someone please ID this object, it is like a black egg or cocoon? Approx 6/7mm in diameter.

I have seen these several times. This one was discovered under some old black polythene beside a sheep feeder, in rough hilly pasture. Can someone please ID this object, it is like a black egg or cocoon? Approx 6/7mm in diameter.