Years ago I was exploring a narrow canyon off the Escalante River in southern Utah. It was a box canyon that pinched out behind a stand of willows. I wanted to see the source of the little stream I'd been following but just as I started into the willows I looked down and saw a VERY fresh paw-print in the mud. It was definitely the track of a big cat that was just beginning to fill with water.
I suddenly lost interest in exploring and backed away as quietly as possible. I must have walked backward about a quarter mile, watching intently for any sign of movement from the willows. Luckily for me the cat wasn't hungry at that moment. I'd have been easy pickings.
I was hunting elk in the back woods near Two Dot in Montana one year. I had a nice perch sitting on a ridge with plenty of sign that the elk were moving through into the lower fields at night to feed. Just as it was getting dark enough I had to leave a fricking mountain lion let loose with one of its growls and I swear to God it was just a couple of feet behind me. I spun around but the brush and darkness kept me from seeing anything further than about 5’ from my nose.
It was a long, dark walk out of the woods alone that night.