Look up 'Panic in the Woods Phenomenon '.

It's been reported since Ancient Greece or even further back.

It goes well beyond normal fear of being hunted. It's the Fear you talked about. Even from experienced hunters and soldiers armed with high-tech, military weapons. Rangers and Green Beret types have talked about sudden, pants-shitting fear just out of the blue, middle of a nice calm day, type situations.

The idea I'm touting is that the Greek God Pan - who Satyrs and even Satan/the Devil's appearance is based on - could have, itself, been based on a Fleshgait.