The lag is a problem with your computer not being able to handle Minecraft try assigning some more ram.
I have has this happen on a map I am working on, I summon a Baby Zombie and when it runs around for a bit it falls right trough the floor and dies of fall damage. The Baby zombie only been one block tall, on a one block platform, when it falls trough one block, it falls to the ground
I fixed it! Had to re install Minecraft, restart computer and then restart again.
https://mojang.atlassian.net/browse/MC-37370
The URL above is the bed texture glitch
I have tried relogging - I do not have a texture pack or resource pack.
Isn't that intended?
If anybody has any information to help me, please leave a comment! Thanks - Ben_Andy
That is your computer not being good enough to handle Minecraft, assign more ram to the game