Ok. So I just got the update and started to build some houses on Creative. When I would dig down past stone level the screen would go black and I couldn't see anything!

I got the update today and I was so excited to build a house with the pink stained glass and use the new fishing mechanics. So I built a huge house and was making a basement. So I wanted the basement to be deep so I went past stone. I expected to just see stone and dirt. I did for a few seconds. Then when I started building the screen went black. At this time I had an Eight Minute Night Vision Potion in effect. I turned the sound up on my headphones and I heard growling. Yes you read that right growling. It was a scary growl like the growling that people think Herobrine does. Now personally I don't believe in Herobrine but the update list says "removed herobrine" so I don't understand what's happening! This event has happened to me twice. Both times I had the potion in effect. The first time I got out of it by clicking and stuff. The second time I couldn't get out of it so I had to save and quit. Now this sounds crazy but when I was building the house I saw a nametag in the ground. I was probably just imagining it but still, creepy. I'm not sure how to reproduce it. I was on Creative, I used super flat tunnelers dream, I dug past stone and boom. I also had cheats on, bonus chest off, and structures off.
Thanks for reading my bug issue!