Just in case the direct link doesn’t work properly: https://i.imgur.com/IgbRs9y.mp4
PS: The mushy thing they’re standing on might be a cluster of Giant Salvinia, a floating water plant that can create extemely buoyant “islands” up to 60 cm thick.
EDIT: More likely a floating mat (Thanks again!)
This seems like some shit dudes from 10,000 years ago would be doing
This video is from 8841 years ago, so pretty good guess!