what on earth is this?

[parsleythelion]

i found this in a bird box i put up this year. it feels a tad spongey yet tough. also there are gouges out of the wood inside the box around the 'object'. is it a spider's lair or some sort of hive?

[Ukwildlifeo]

Could be a bumble bee hive. They often use bird boxes and it looks similar to something I found under some wood, before a few bees started buzzing angrily and I put it back down!

[Jason Green]

I thought at first it was a strong-looking web, but the gouges suggest a bee/wasp nest.

[Ruth Daniel]

Could it be a Hornet?
I have heard of them using birdboxes and the gouges in the wood would suggest wasp like behaviour?