Using the inverted or upside down devil's horns has 2 meanings. Most often seen at
Goth and Industrial shows or in Gothic night clubs, it is used as it resembles Vampire fangs and to say "metal sucks". Both relaying to those around you that you simultaneously support the
Goth scene (though most Goths detest the Vampire scene, the gesture is used tongue in cheek) and condemn the metal scene, or those who confuse the
two. It began as a backlash against new comers to the
Goth scene (or neos) who don't understand that
Goth exists not as a compliment to the metal scene, but as it's antithesis.