A characteristic of pre-credit scenes in the horror genre is a character (seemingly a main character) who is killed quickly, as a heralding "warning kill" of the antagonist.

Directors often expended a significant percentage of their films special effects budget on these bloody pre-credits forcing low budget indie film directors to find innovative ways to match these CGI created gore soaked pre-credit spectacles.

Some less scrupulous indie directors, in their quest to save budget, skipped the special effects entirely...