Put the summary of the bug you're having here

What I expected to happen was...:
Be able to play the game comfortably.

What actually happened was...:
When I walk I can see the underworld and other blocks underneath along with random ones clipping in the sky and rotating.

Steps to Reproduce:
1. Play Minecraft on my computer
2. Walk or sometimes not even required
3. Laugh at how annoying it must be to be trying to play with this bug.

In the attachment you can see a little taste of what is happening. I can't get much of a better shot because it's constantly flickering and seems to never be captured when I take a screenshot. Any help regarding this would be extremely useful. I have messed with almost every settings combo in the video settings but nothing has made it better nor worse.