Monster High: Great Scarrier Reef (2016)

Join your favourite ghoulfriends in an all-new aquatic adventure! When the ghouls get pulled into the school pool, they're transported to the gore-geous underwater world of the Great Scarrier Reef. Lagoon realizes she's come home and, in a fintastic mission of the heart, decides to come to terms with her own freaky flaws. Of course she'll need help from the most creeperific firends ever as she confronts a frenemy from her past, competes in a scaretastic dance extravaganze, and fights a terrible beast from the deep!

Unfortunately the movie Monster High: Great Scarrier Reef is not yet available on HBO Max.