I've had gators calling less than 10' from my hammock.
I had a hunter take a shot on the first day of gun season without ever seeing my setup. Fun way to wake up!
I've had a bear immediately on the other side of my tarp snorting around.
I've found coyote tracks under my tarp in the morning...that weren't there the night before!!!!
I've been lullabied by wolf calls in the middle of the night. Course there were about twenty of them up the hill...all in their pens.
I heard a sound in the Smokies that I still haven't been able to ID and still keeps me awake from time to time.
I had a dream I was falling, but didn't wake up before I hit. Turned out, I was falling and I dang sure woke up when I hit!
I've had a squirrel stand on my ridgeline, right above my face, and yell at me to "WAKE UP"!
I have pretended to be a lighthouse with my headlamp more times than I could ever hope to count, trying to find whatever made 'that' noise.
But, the thing that scared me the most, was the wind. First time I was tied to a tree of small diameter and a storm came through in the middle of the night, I learned the value of large trees. See, the leaves in the canopy of the small trees act like a kite and trap the wind. When it does that, it moves...a lot! As it happened, it was the head-end of my hammock that was tied to the little tree. When the big gust of wind came, it felt like someone kicked my head from under the hammock. I was bounced awake and on full sci-fi/horror film alert. Probably pretty easily, the most scared I've been in a hammock. It only lasted a moment, but I remember it well.