When loading into a world, clouds will be seen at ground level 60. It will show that you're 150 blocks above. Entities will originally spawn at there ground level when the world was first logged off, and loading into this version will make all the mobs suffocate underground. All chests will be cleared and empty. Also making them glitched, double chests will turn into individual chests. Water turns into ice at that level and whatever happens at 150 height.