(Sorry for Confusion) 8 is a Username, certain now!

(Edited to correct user; I must have mis-typed!) I don't know how this person got it, or why, or whether it's just a Mojangster or an easter egg, but ages ago the user "8" logged into a server I was playing on. I was recently reminded of this and looked it up on the username search engine "NameMC", and it still exists. How is this possible? A glitch or bug maybe? If so, can other people get single and double digit names? (Because that would be cool!) Ah, well.