I have ran into way too many snakes - just plain old gardner snakes - while caching. I have added a paper bag to my caching gear because no matter how small they are, I always hyperventilate when I see them. After that first time, standing on the trail with my head between my legs thinking I'm going to pass out and this is how they will find me, I keep that bag in a very handy spot!
I have also seen a big bull elk come crashing through the woods and stop about 50 feet from the cache - we all looked at each other for about 15 seconds until he skeedaddled back into the woods - guess he realized he would not get the FTF!
The deer I have seen have been much braver. There were two standing right at GZ, I kept thinking they would run off as I edged forward. They finally backed up a bit, sat down and decided to watch the wacky lady in the woods as I grabbed the cache.
I was also follow for a while by a coyote and saw a big pheasant/quail type bird (I don't know my birds) - but it was good sized, on the ground and unusual looking. In the same area I have seen a beautiful gray wolf. I saw it before I stopped to get a cache and decided to go elsewhere since I was by myself.
But my all time favorite was an evening I went out - it was already getting dark, raining and I forgot to "mark" where I parked with the GPSr. After a few turns on different trails, I realized none of the trails where marked - should I turn around or continue? Continue of course! Well, I found the cache, decided to get another on in the area and I was heading back to the general area on the car - completely soaked at this point and a bit cold. Came to yet another Y in the trail, choose one path (neither went where I was interested in going) and started heading down it. Suddenly, there was a low growl from behind me. Dreading what could be back there, I slowly turned around (imagination running everywhere at this point) and the flashlight revelled a dog - thank goodness, just a dog! I yelled at it to go home, which worked for a minute until I heard the growling again and so I stopped and yelled at it again to go home when I heard "Hello?". I was releived, and felt a bit sheepish, for yelling at this guys dog in the woods - but it was dark and this guy didn't even have a flashlight, but he did know the area. He helped me get out of the woods and back to my car, and the doggy didn't growl at me the rest of the way[]