Step right this way for the year's first relentlessly derivative horror cheapie. More than a century ago in the town of Darkness Falls, a neighborhood predator was put to death by a mob of angry parents. Now her malign spririt haunts the luckless hamlet, invading the bedrooms of tots who leave their precious molars and incisors under their pillows for the fabled Tooth Fairy. If you're thinking "A Nightmare on Elm Street" with gingivitis, you called it. At least the limp, low-budget shock tactics are leavened by sporadic moments of humor -- some of them even intentional.