A mad scientist (Donald Pleasence) crosses plants with people, and the results wind up in a sideshow.
You can now watch The Mutations online on the following streaming providers in the United States.
| Directing | Jack Cardiff | Director |
| Writing | Robert D. Weinbach | Screenplay |
| Directing | Ray Freeborn | Second Assistant Director |
| Costume & Make-Up | Charles E. Parker | Special Effects Makeup Artist |
| Camera | Paul Beeson | Director of Photography |
| Production | Brad Harris | Associate Producer |
| Production | Sally Nicholl | Casting |
| Art | Josie MacAvin | Set Decoration |
| Production | Herbert G. Luft | Associate Producer |
| Editing | John Trumper | Editor |
| Writing | Edward Mann | Screenplay |
| Art | Herbert Smith | Art Direction |
| Production | Robert D. Weinbach | Producer |
| Sound | Basil Kirchin | Original Music Composer |
| Production | J. Ronald Getty | Executive Producer |
| Costume & Make-Up | Susie Hill | Hairdresser |
| Production | Jack Smith | Production Supervisor |
| Production | Alfred W. Marcus | Production Manager |
| Directing | Brian Dunbar | Assistant Director |
| Directing | Gareth Tandy | Third Assistant Director |
| Sound | Mike Le Mare | Sound Editor |
| Sound | Peter Bond | Assistant Sound Editor |
| Editing | Russ Woolnough | First Assistant Editor |
| Editing | David Beesley | Assistant Editor |
| Sound | Ted Karnon | Sound Mixer |
| Sound | Brian Ford | Sound Mixer |
| Camera | Ray Sturgess | Camera Operator |
| Sound | Danny Daniel | Sound Recordist |
| Sound | Stan Haines | Boom Operator |
| Camera | David Worley | Focus Puller |
| Directing | Doreen Soan | Continuity |
| Crew | Eddie Powell | Stunts |
| Costume & Make-Up | Paul Vachon | Wardrobe Master |
| Art | John Lageu | Assistant Art Director |
| Art | Josie MacAvin | Set Dresser |
| Camera | John Jay | Still Photographer |
| Production | Ray Tranter | Production Accountant |
| Crew | Mike Hope | Special Effects |
| Costume & Make-Up | Joanna Wright | Wardrobe Assistant |
| Costume & Make-Up | Kay Freeborn | Assistant Makeup Artist |
| Costume & Make-Up | Robin Grantham | Assistant Makeup Artist |
| Art | Bob Devine | Construction Manager |
| Lighting | John May | Electrician |
| Production | Lynda Levy | Production Secretary |
| Production | Jeanne Ferber | Production Secretary |
