The Ghastly Ghoul (2023)

Every year, the monsters from Halloween Town come to Earth to trick or treat for one glorious night of mischief before the gateway back to their world closes again. The Ghastly Ghoul is the story of Gary, a cute little monster who doesn’t believe he’s scary enough and so disguises himself as the Ghastly Ghoul. When he misses the gateway back home, he is trapped in the human world. He forms a friendship with a young girl, Beatrix, who is struggling with her own fears around the macabre holiday and together they help inspire a sense of self-belief in one another and try to find a way to get Gary home again on a Halloween night filled with magic and adventure.

Unfortunately the movie The Ghastly Ghoul is not yet available on HBO Max.