Cork Mystery

I opened a bottle of Rioja and drank 2/3 of it. I then replaced the cork and left it in my cool utility room. Three days later I returned to the bottle and found that at the junction between where the bottle met the reinserted cork there was what looked like a ‘mushroom’ growth ‘sprouting’ from the cork. On closer examination, the ‘mushroom’ like growth seemed to actually consist of fine cork granules held together with some very fine silken like threads.

See photo.
[The ‘mushroom’ like structure fell off when I pulled out the cork. You can see a sort of depression or hole on the cork where the ‘mushroom’ was attached.]

What is it???
Has anyone seen/experienced this before??

I am just wondering if it is perhaps related to some kind of insect seeking ‘liberation’ after living in Nirvana for 7 years – it is a Reserva after all and seems like somewhat ungrateful behaviour…?

Other experiences or expert opinion, gratefully received… !


Cork worm? Not something, fortunately, that’s happened to me, but ISTR it has been mentioned here before (perhaps as “cork weevil”)