The opposite of the Halo Effect is the Devil Effect?  And comics can be made by copying Wikipedia text verbatim and pasting it onto drawings of hot chicks?  Why aren’t I in this business? 

Why not the pitchfork effect?  Or the Bifurcated Tail Effect?  Or the Brimstone Effect?  I can think of a dozen better names for “things that are obverse to halos” than ‘Devil’.  And this is to say nothing of the more likely celestial —in the non-theological sense— origin of the term referring to the bands of colored light surrounding a light source, caused by refraction, making the light source appear larger.  Oy.