My childhood dog was a pretty sizeable Bernese mountain dog that was incredibly aloof and chill while I knew her. We would joke that if robbers ever broke in, the most protection she would offer would be falling asleep on the valuables. My mom would always tell us a story about how she went hiking one time with the dog and like 15 minutes in our dog hunched over, started backing into my mom and started growling like a lawnmower. This was pretty out of character so my mom turned turned around nearly immediately. The walk back was pretty tense with the dog pacing and letting out some nasty barks here and there but my Mom didn’t know what was up with her until she stared noticing the big mountain lion tracks that zigzagged along the mud on their way back down. They got out fine and I never saw the dog act like that once in my life but I can only imagine how scary it must have been. Mountain lions are freaky.