I do a lot of solo backpacking in the backcounty in northern Minnesota and I have had some "odd" experiences in the past.
This is my most recent.
Last August, I was dispersed camping in the Finland State Forests. Dispersed camping is where there are no trails and you are just trekking through the bush and set up camp wherever you want. No permits, no cell service, no people. I usually just park my car in a ditch off of an old logging road and head into the woods. My family knows of my general location and I have a SPOT satellite transmitter if things should go bad. I was 3 days into the woods and about 8ish miles from my entry point and it was well past dark at this point. I had put my small campfire out for the night and I was reading a book in my camping hammock. If you haven't even been in the north woods, it gets really dark at night.
So dark that you can't see your hand in front of your face if the moon isn't out. After about an hour of reading, the woods suddenly got really quiet. Then I heard some footfalls/crunching in the woods followed by a large tree fall in the distance. The sound of a tree falling in absolute silence is very unnerving and it was followed by 2 more tree falls within the next few minutes.
They all seemed to stay a fair distance away from me, but close enough for me to get out of my hammock and fire up a campfire again. I have learned to keep a reserve of quick burning kindling/wood for instances like this and I am glad that I did. I never did see anything and I didn't go looking for it. Whatever it was decided to move on once I had my fire going again. It was probably a large predator of some sort or a moose, but it really freaked me out.
I still go of grid whenever I can, but that experience freaked me out more then usual.