Nest or fungi?

Nest or fungi?

Observation - Nest or fungi? - UK and Ireland. Description: Light grey, papery(?), quite firm (have given it a gentle prod with a stick). I noticed it about four days ago and it hasn't changed since then. One penny piece for scale.

Light grey, papery(?), quite firm (have given it a gentle prod with a stick).
I noticed it about four days ago and it hasn't changed since then.
One penny piece for scale.