I used to watch Paulsoaresjr's "Survive and Thrive" series. In the second series (after the game was released) he started to call skeletons in full gold armour "Skelebling". I don't know why but I remembered this and when I got to pick my username for my account back in 2013 I thought Skelebling sounded cool. I had thought about changing it but decided not to after I started using it on other platforms like Steam and social media. 4 years later and I have never changed my Minecraft account's name, and never intend to.
Slightly off topic but, it seems like sleketons are the most frequently nick-names mobs in Minecraft, I've heard, Skelington, Skelebob, and Skelly, and now Skelebling.
I chose my name from back in the Halo Days. I wanted something unique. So one day I was sitting there killing people and laughed because on the sceen it said you were killed by "alolipop". Thats when it clicked and became aNaturalCause. So now when I kill people, which doesn't happen very often it says you were killed by "aNaturalCause". Thought it would be funny because being shot in a game is not a natural cause.
That's funny, I thought of making my username "YourBoss" so that it would say things like "YourBos has entered the game". I didn't because I thought it would probably already be taken, I also thought of "TheHoodedOne" or "TheHooded1" but they were both taken. There are all kinds of names that could be very funny when they show up in the game chat.