I had a world that said "This world cannot be opened", so I created a new world to transfer it's CURRENT file, to fix the error, but I had forgotten to enter the seed of my world. When the world opened up, I wanted to explore it for a little bit. After a few seconds of walking around, I found a ice spikes biome. I wandered around a little bit, until I saw some unusual things. First, I saw 3 sea turtles spawn, a few blocks away from the ice sheet, and that means that the seed had generated a warm beach right next to a cold biome, which shouldn't happen. The next thing I saw, was a structure, composed of gravel, cracked cobblestone, and mossy cobblestone, sitting on top of one of the ice spikes. I climbed up the ice spike, and went in the structure. I removed some ice from the floor, and I found a chest, sitting next to a block of magma. Inside the chest, was a piece of rotten flesh, a treasure map, and some wheat, spread out across the grid. I'm assuming that the structure was supposed to be underwater, because of the magma block, and the game probably thought that the glacier was water. The third strange thing I saw, was lily pads on top of the ice sheet, again, it was probably the game thinking that it was water. The last thing I saw was a small glacier inside of a small lake, in a forest biome. I don't know how this happened. If you want to try this seed out for yourself, the seed is -1027737731. This might not work on console, or Java, because they have different world generation systems.

I have provided some screenshots of the discoveries below.