An American Tail: The Mystery of the Night Monster (1999)

Storyline:
Follow the clues to fun and excitement as the beloved little mouse takes on a big monster in this charming, full-length adventure. When a ferocious, mouse-nabbing creature puts fear into the hearts of New York City's rodents, Fievel and his friends team up with a reporter to chase after the scoop of the century and -- just maybe -- get a close-up look at the bad guy himself!