That one is defintely ace.
The best for ages out of a generally very high standard. It's the blue layer that does it, although I couldn't precisely say how.
(
Matazone has new icons, but is keeping this one,
Mon 3 Mar 2008, 23:39,
archived)
I'd take a uneducated guess along the lines of
it's becuase it's the inverse of what the correct shading there should be where it should meet the black background, so it manages to border the image without it standing out and clashing horribly.
(
StickFigureNinja is worried he may be on the list,
Mon 3 Mar 2008, 23:42,
archived)