I think it's a german invention.. 'Sitzrucksack'. Crossed my mind that sitting on one up against a tree under a camo net might be comfortable if a bit bitey. One could always offer the hairy guy a seat. But then there's all those stumps around!
https://www.amazon.co.uk/DAM-angler%C2% ... B0026PBGLY
A Think Tank of Techniques and Technology.