Every once and a while, the whole minecraft world, especially when loading a new world or when reloading chunks, will start to bug out and copy/paste ghost chunks everywhere, spazzing out the screen. Any mobs in the area during this time also begin to glitch, and become weird looking, conglomerate messes of textures (and it spooks me out). I've got some examples from just today, and also times before from 1.8.9 and earlier.

In case you're wondering, here's a description of what's pictured (possibly out of order).
-Not sure, but it might be a chicken.
-Far away Guardian
-Lots of sheep and a house
-Snowman (twice)
-Inventory Chest (normal chest not glitched for some reason???)
-Village view (sure is big)
-View from my Survival Bed (faces a wall)
-Gray Inventory
-Apparently I dug below bedrock to more stone, cool. (Mineshaft)
-Probably a chicken. From several chunks away.
-Believe it or not, a dog.
_UNPICTURED
-Spider turns into wicker board and/or giant death cloud
-Villager becomes arms
-Endermite turns into purple square spanning at least a chunk
-Enderman turns into jaws. (No not the shark, I mean its jaw)

For any extra clarification here's a video I made from a while ago:
https://youtu.be/FTgejmWc8vk?t=20s