You're missing the point, they want to have a reference-able name.
An invisible character isn't the right direction
and @ op, I have no creativity whatsoever but do something that you like. Maybe a tv character or a movie character or something that you relate to, and if your real name is kinda funky (hasn't been used yet) do that!
Judging by my username you can tell I don't have much creativity
One word of anything will do honestly. Kinda impossible for us to find something that will suit you because its all about what looks good in the eye of the beholder. You pick something and own that bitch with a sig, make it stand out.