A wannabe Invisibob is basically someone who can't be an Invisibob, but wants to be.
Therefore, they wear normal clothes, yet hide their face so as to remember our radioactive, floating, boxer-shorted, invisible friends.
...See Gaia Online.
"Kenjoki, you are SUCH a Wannabe Invisibob!"
"You are an Invisibob Wannabe. Take off those masks."