A new and dangerous trend has led children nationwide to suffer serious burns and, in at least one case, death. The “Hot Water Challenge,” which kids say was inspired by YouTube videos, involves pouring boiling water on an unsuspecting friend — or, in one fatal instance, daring a friend to drink boiling water through a straw. On Monday, an 11-year-old Jamoneisha Merritt of the Bronx was badly burned when friends poured boiling water on her face while she slept.