Corn grain contaminated with steroids produces large rats the size of small dogs who begin feeding on the residents of Toronto. Paul, a college basketball coach, teams up with Kelly, a local health inspector, to uncover the source of the mysterious rat attacks and they eventually try to prevent the opening of a new subway line as well as find the mutant rats nest quickly, or there will be a huge massacre of the entire city!
| Directing | Robert Clouse | Director |
| Writing | Charles H. Eglee | Screenplay |
| Writing | James Herbert | Novel |
| Production | Paul Kahnert | Producer |
| Production | J. Gordon Arnold | Executive Producer |
| Sound | Anthony Guefen | Original Music Composer |
| Art | Ninkey Dalton | Art Direction |
| Camera | René Verzier | Director of Photography |
| Editing | Ron Wisman | Editor |
| Production | Jeff Schechtman | Producer |
| Production | Cathy Henderson | Casting |
| Costume & Make-Up | Allan A. Apone | Special Effects Makeup Artist |
| Costume & Make-Up | Douglas J. White | Special Effects Makeup Artist |
| Costume & Make-Up | Francisco X. Pérez | Special Effects Makeup Artist |
| Costume & Make-Up | Kenny Myers | Special Effects Makeup Artist |
