Slimey Slime McSlimington, from a page of this sources back in the old Internet. For additional reference "twink" used to refer to a tabletop RPG munchkin or power gamer; not the, uh, not the other thing.
As far as I've seen it's the oldest example of the "namey mcname" joke out there.
The answer is that there's no one answer. Since people find it, since people make it, and some people don't think it exists. I'm that last one, just killing time until sweet oblivion finally claims me.