Lois Wolobah got a call Friday from the nurse at her son’s high school in Worcester, Mass. Harris, a sophomore, had fainted after eating a tortilla chip. When Wolobah got to the high school, her son showed her an image on his phone of what made him sick — a single “extremely hot tortilla chip” encrusted with seasoning from some of the spiciest chile peppers in the world, packaged in a coffin-shaped box emblazoned with a snake slithering through the eye of a skull.