Leonardo is truly a terrible monster-terrible at being a monster that is. No matter how hard he tries, he can't seem to frighten anyone. Determined to succeed, Leonardo sets himself to training and research. Finally, he finds a nervous little boy, and scares the tuna salad out of him! But scaring people isn't quite as satisfying as he thought it would be. Leonardo realizes that he might be a terrible, awful monster-but he could be a really good friend.
Unfortunately the movie Leonardo, the Terrible Monster is not yet available on HBO Max.
| Writing | Mo Willems | Writer |
| Visual Effects | Mo Willems | Animation |
| Sound | Joel Goodman | Music |
| Sound | David Bramfitt | Music |
| Visual Effects | Pete List | Animation |
| Directing | Pete List | Director |
| Production | Paul R. Gagne | Producer |
| Production | Mo Willems | Producer |
