I entered the end and played then I knew something was up.. I got in and the textures were missing it looked like a horror map

I played for about three mins before a huge pool of red appeared I was frightened I then saw the purple and black (texture missing) but it wasn't a block it was unsold and you could walk through his breath was missing everything was glitched and untextured I got a horrible headache so I had to put my items in a enderchest and jump off (I think this texture is dangerous to people with epilepsy too)