These guys
The gimmick: dresses up all in black (with some eyeliner) and and claims be a horror rock band (in their words, "violent/ dangerous pop"). This "horror" theme is present on their album covers (blood)
Why the gimmick doesn't work: Their songs are the the most unhorrific things ever. This so-called horror theme is not present at all. Thus, the problem is their too concerned about the image and not the music.