So I had a "fun" experience last night. The newest planet I landed is radioactive with occasional storms. I found one of those really tall towers of gold that go deep in the ground and was mining it for awhile. When I jumped in the hole from where I had been mining to get more of the gold, I noticed the ground polygons on one side of the hole were missing or invisible, although some would show up if I ran the mining beam over them. I hadn't seen that before, but I shrugged it off and when I was done mining I jetpacked out of the hole and went off exploring.
After I was done exploring the area, I headed back to my ship and passed by the remains of the gold tower. Too close it seems, as when I got to the part with the messed up polygons I fell through the ground and ended up partially stuck in the surface. I could move around, but I couldn't get above a certain point. I ended up in the water and I could get above the surface a little bit, but I couldn't get out completely. As I moved around I was always seeing like the "edge" of the world.
I was stuck in the water and while I could sometimes get out enough so I didn't drown, I was getting constant radiation warnings. I was getting to the point where I was thinking it might be best to just let my character die, but in the weird state I was in, I didn't know if I'd be able to recover my goods, and, dammit, I had mined a lot of gold. I kept recharging my ant-radiation system and soldiered on when I finally came to a part where I saw a bunch of stalactites below me. The tops of the stalactites were flat so I was able to walk on top of them and get out of the friggin water.
I then thought I'd try shooting some plasma grenades. They hadn't helped when I was stuck in the water, but here I could see they were having some effect in the distance. I carefully walked along the top of the stalactites occasionally firing plasma grenades and finally I created some kind of hole and fell into the cavern I'd been walking on top of. Whew! What a relief. Now I was wondering where my ship was since I'd moved around quite a bit trying to get out of my predicament. It turned out I was right below my ship! A storm warning came through, so I waited it out, but after I started firing grenades at the ceiling. After about ten grenades I finally saw the sky and was able to jetpack out, and there was my ship!
Finally out of my predicament I chalk it up to encountering an anomaly on the planet and just another strange part of my journey, and a lesson to stay away from strange polygons.