Walldude called himself that because his job was setting up a video wall (Tiled screens I think) at trade shows, he foolishly bragged of getting over some political shenanigan on the job but was outed on his mad boast by one of our more sleuthy members, and lost his job over it.
There have been many idiots since who have emulated his folly, but 'Walldude' has become our word of choice to describe a DUer who brags of some misconduct on-line but is then revealed and fired/disgraced for that ill-considered braggadocio. Walrus-puss for hiding the remote at the car dealership where he worked, Kali (Was it?) for bitching about the earwigs at the restaurant where she was slightly-employed, and several others.
Nor is that the only word DU has birthed, for instant 'Bouncy' stories all go back to the paradigm of DUer Bouncyball's improbable yarns. And, of course, nearly everyone recalls what it means to 'Nadin' something.