Sun started flashing, then became a flattened donkey with chests texture

Put the summary of the bug you're having here

I was in my survival world, and approaching the stronghold with eyes of ender. One of them had broken before and may have caused this. Up until then everything was fine, then the sun started flashing a lot whilst it turned to night, and eventually turned into a texture of what looked like a donkey with chests?

I used the Open to LAN feature to switch to creative for a better view. Reloading the world doesn't fix the texture.