https://www.youtube.com/watch?v=jJtPMO7Y7Tc
You can see at the end of the video there is an invisible zombie following me and beating on me. well u can't see it but u can see it hitting me and me trying to hit it back with no luck. I thought he was under the map so i tried to go to a second floor to see if he would pop up or stop hitting me but he just followed me.