When the Boogey Man causes Grim to lose his powers, rank, and title in the Underworld Court for misusing his powers, he plots to seek out Horror's Hand and take over the world. It's up to Billy, Mandy, Irwin, and Grim to get to Horror's Hand before the Boogey Man does.
Unfortunately the movie Billy & Mandy's Big Boogey Adventure is not yet available on HBO Max.
| Sound | Glenn Oyabe | Sound Editor |
| Art | Cliff Voorhees | Background Designer |
| Visual Effects | Hyung-tae Kim | Animation Director |
| Visual Effects | Phil Rynda | Color Designer |
| Visual Effects | Soo-hyun Park | Animation Director |
| Production | Louis J. Cuck | Producer |
| Directing | Sue Perrotto | Director |
| Directing | Kris Sherwood | Director |
| Writing | Frank Homiski | Characters |
| Writing | Eva Wu | Characters |
| Directing | Matt Engstrom | Director |
| Directing | Eddy Houchins | Director |
| Production | James Silverman | Production Manager |
| Sound | Timothy J. Garrity | Sound Re-Recording Mixer |
| Writing | Joe Binggeli | Characters |
| Directing | Shaun Cashman | Director |
| Production | Kris Zimmerman | Casting |
| Art | Don Watson | Background Designer |
| Production | Jennifer Pelphrey | Producer |
| Editing | Illya Owens | Editor |
| Sound | Eric Sequeira | Sound Re-Recording Mixer |
| Directing | Russell Calabrese | Director |
| Art | Marc Perry | Art Direction |
| Crew | Mark Bachand | Prop Maker |
| Sound | Robert Serda | Sound Engineer |
| Directing | Phil Cummings | Director |
| Directing | Gordon Kent | Director |
| Directing | Michel Lyman | Director |
| Crew | Anna Chambers | Prop Maker |
| Production | Shaun Cashman | Producer |
| Sound | Jesse Arruda | Sound Editor |
| Editing | Jim Hearn | Dialogue Editor |
| Visual Effects | Azariah Owens | Visual Effects |
| Editing | Rob Desales | Editor |
| Crew | Alicia Parkinson | Post Production Supervisor |
| Production | Shalonda Ware | Production Accountant |
| Production | Pietro Piumetti | Producer |
| Writing | Marc Perry | Characters |
| Production | Ben Pile | Producer |
| Directing | Christine Kolosov | Director |
| Visual Effects | Joo-Shik Yoo | Animation Director |
| Visual Effects | Lee Jae Bok | Animation Director |
| Production | Jay Bastian | Executive In Charge Of Production |
| Visual Effects | Kwang-bae Park | Animation Director |
| Production | Brian A. Miller | Executive Producer |
| Crew | Tony Tedford | Post Production Supervisor |
| Sound | Brad Brock | Sound Re-Recording Mixer |
| Visual Effects | Sandy Benenati | Animation |
| Crew | Antonio Gonella | Supervising Technical Director |
| Directing | Robert Alvarez | Director |
| Writing | Nina G. Bargiel | Writer |
| Writing | Maxwell Atoms | Story |
| Writing | Jeremy J. Bargiel | Writer |
| Writing | Maxwell Atoms | Writer |
| Art | Tara Whitaker | Storyboard Artist |
| Art | Jay Baker | Storyboard Artist |
| Art | Chris Headrick | Storyboard Artist |
| Art | Chris Mitchell | Storyboard Artist |
| Art | Maxwell Atoms | Storyboard Artist |
| Art | Shaun Cashman | Storyboard Artist |
| Art | Spencer Laudiero | Storyboard Artist |
| Art | Mike Diederich | Storyboard Artist |
| Art | C.H. Greenblatt | Storyboard Artist |
| Art | Ian Wasseluk | Storyboard Artist |
| Art | Alex Almaguer | Storyboard Artist |
| Art | John Holmquist | Storyboard Artist |
| Writing | Maxwell Atoms | Characters |
| Production | Maxwell Atoms | Executive Producer |
| Art | Bill Flores | Background Designer |
| Sound | Drew Neumann | Original Music Composer |
| Sound | Gregory Hinde | Original Music Composer |
| Sound | Kris Zimmerman | Sound Director |
| Art | Joe Binggeli | Background Designer |
| Directing | Juli Murphy | Director |
| Writing | Phil Rynda | Characters |
