I logged on to my world and, diffrent buildings in villages were pooping up on every piece of land. they would switch building to building too. Also grass blocks on the ground would switch directions paranormal.

It was a nightmare. I logged on and.. Boom! my world went crazy. the grass blocks below me were switching directions ghostly and my master pieces were turning in to plates of bedrock. When i flew up high every block in the whole world was covered in blacksmith shops, then a normal house, then back to a castle, and just keep switching. I looked closely and saw a giant monster diving under the ground. Something that which looked like an enormous wither boss. I tried restarting my game, getting onto different worlds, and more. this just happened when i updated to minecraft 1.9 And its never happened before.