The two of us were playing in a new world in Multiplayer mode on our home wlan, when after about 5 hours a wither or ender dragon spawned above us. I (the remote player) was killed almost instantly. My son, the local player, claimed it was a wither. We left the game and I analysed the database with "mcpe_viz". I could not find a wither, but I found an Ender Dragon. When my son went back in creative mode and moved to the location of the dragon we found in the database, it was there - not where I died, but not that far away either. The dragon was destroying the overworld down to the bedrock. We had not been to the nether or end during these first 5 hours and we had played all the time in survival mode, difficulty "difficult".

It happened when the sun was just going down, so maybe a phantom should have been spawned instead.

Attached is the saved Minecraft PE world.

Before this happened we had already experienced other strange effects like monsters spawning in well lit rooms and removed redstone ore stayed as an invisible obstacle (theory: candles placed by the remote player and redstone ore removed by the remote player were not fully taken into account).

Version: 1.7.0.13, Remote plyaer on Asus Padfone 2 with Android 4.1.1