I was on an organised fungi walk and while we stood in a group listening to the leader I looked down and thought the ground was moving. It was a horrid feeling but for meters around us under our feet there was movement (if I dream about them tonight it wouldn't surprise me

). I tried to be discrete and take the photo's, one I didn't want to be rude while the leader was talking and two, I didn't want to freak or unsettle any of the group because there were 6 young children.
I wonder if it was the trampling of a group of 16 people which brought them to the surface or they were there in the leaf litter anyway?
There were hundreds and hundreds of these things. They were about 1 -1.5cm long, I think I saw some legs but can't be sure.
Does anyone know what they possibly could be?