A middle-aged woman is diagnosed with a tumor by a charismatic preacher. She vomits up what she believes to be the tumor. The "tumor" turns out to be a strange spore of sorts that can grow into a carnivorous creature. This spore inside the boy's body now makes him brutally kill people to feed the other spores, which grow into strange creatures as described.
Tumorous parasitic beasts are nesting in the bowels of their victims...