Not sure but

We think it may have been the nest of a queen wasp overwintering in the shed. We first found it last year when we opened up for the first time after winter. There didn't seem to be anything in it. Its about the size of a ping pong ball, beautifully structured as you can see, with a very small hole at the bottom. We left it and its still there this year.

We do often find a wasp in the shed but no sign of a nest.

Interesting, anyone ever come across one.

Mind you it could be an alien space ship with a whole crew living in it.