It's probably minecraft error with the texture pack. Your minecraft texture pack bugged when minecraft loads, and it was a magma cube that teleported from nether with your portal.
(It happened many times to me, but mine was the items)
lol, that's stupid, 2 blocks ceiling house, it will make your house feel like a jail -_- It's simple, just dont look at the enderman or just put a water in your house if there is an enderman and it will disappear.
The first thing i made in minecraft was a farm. I watched a farming tutorial video on youtube, then i try it in an indonesian server without playing single player even once, i made the farm without any tools, only hand, it took a lot time breaking stones, i didn't know anything about minecraft yet. I got attacked by a zombie and i ran into someone's house that helped me out making my farm and teach me a lot things in minecraft