Common Rough Woodlouse

Common Rough Woodlouse

Observation - Common Rough Woodlouse - UK and Ireland. Description: I spotted this hanging in the platelet on the trunk of a large Horse Chestnut Tree. I feel I should

I spotted this hanging in the platelet on the trunk of a large Horse Chestnut Tree. I feel I should recognise it but can't!
I can't decide whether it is a dead insect of the shuck of one.
All help appreciated