National Lampoon's Loaded Weapon 1

Noriyasu is an ordinary third-grader until his life takes a bizarre turn after his mother reads his private journal. To surprise her, he starts filling the pages with outrageous lies-claiming there's a giant snake in the bathroom, he eats pencils for dinner, and pigs rain from the sky. But the real shock comes when these absurd stories start happening in real life, and everyone acts as if nothing is out of the ordinary. The chaos only grows when he tries his hand at journalism, writing "fake news" that somehow becomes the talk of the town-including one story that spirals into a disastrous pig-themed apocalypse.