Entity Death

"2 Weeks ago I was on minecraft with one of my freinds. We were helping each other getting diamonds and we built an underground mansion. We built dispensers filled with poisoned arrows and 30 buttons and we were the only one who knew the correct button. If you clicked more than 10 buttons you would fall into a lava pit, just to make it more safe. It was all normal until I saw redstone everywhere. I asked my freind what it was and he just said 'That's free Redstone! YUSSS FINALLY SOME ITEMS WITHOUT HAVING TO MINE THEM' Then I saw some kind of entity in the distance. I got out my sword. I wanted to find out what it was. It was entity 303 just with a black cloak and red eyes. It said 'Hello, I have came to end your strength, Your freind can try to get past, But with me that's not possible.' My freind just ran into the base into his room and locked the doors. I got out my Security Camera mod to see he just got in through the entrance. He must have been watching us build. His username was 'Entity Death' and that freaked me out. There was only 3 People in the server. Me, my freind and the freaky guy. Then he came in. Stay tuned for part 2."