In the fanfiction, a possible plot could be that Beetlejuice has a bet with another character that he can make Adam do something really out of character, like break a major rule in the afterlife. As Beetlejuice tries to get Adam to do this, Adam starts to learn more about himself and his own capabilities. Another idea is that there is a magical object in the musical world that Beetlejuice and Adam both want for different reasons. They start off as rivals for it but then realize they can achieve more by working together. And, there could be a plot where Adam gets lost in a strange part of the afterlife and Beetlejuice has to find him, during which they both grow as characters.
One idea could be to explore Beetlejuice's backstory in more detail. Maybe show how he became the mischievous spirit he is. Another could be a love story within the Beetlejuice musical universe, like a character falling in love with a ghost. Or perhaps a story where the characters have to deal with a new, even more powerful supernatural threat.
One idea could be that the reader is a new resident in the haunted house where Beetlejuice lurks. They accidentally summon him while trying to fix up the old place. Another could be that the reader is a medium who can see Beetlejuice clearly and they form an unlikely friendship. Maybe the reader is a lost soul like Beetlejuice and they find common ground in their otherworldly existence.
Well, in the story, their relationship could start with Adam being a bit afraid of Beetlejuice. But as Beetlejuice shows his softer side, like when he helps Adam deal with his past regrets from his living days, Adam begins to warm up to him. They could also develop their relationship by collaborating on a project, like redecorating a spooky old house in the afterlife. As they work side by side, they learn more about each other's personalities and quirks. Additionally, they might have a moment where they save each other's lives, which deepens their bond.
Perhaps a plot where Lydia and Beetlejuice accidentally swap personalities. This would lead to all sorts of comical and spooky situations. Beetlejuice in Lydia's body would have to deal with school and her family, while Lydia in Beetlejuice's body would have to handle the chaos of the Netherworld. They then have to find a way to switch back before it's too late.
Well, a plot could involve Adam being sent on a mission by some other powerful entity in Hell to infiltrate the Hazbin Hotel and disrupt Charlie's plans. However, he ends up falling for Charlie and has an internal struggle between his loyalty to his original mission and his newfound feelings. Or perhaps Adam has a special power that Charlie needs to help with a big event at the hotel, like a demon - friendly concert, and they have to work together closely to make it a success.
One plot idea could be Lucifer seeing a different side of Adam that no one else has. Maybe Adam shows kindness towards a lower - class demon, which makes Lucifer question his own views. Another could be that they team up to solve a mystery in Hell that threatens both the sinners and the native demons. And a third idea is that Adam tries to introduce Lucifer to more 'human' concepts like forgiveness, which Lucifer initially resists but gradually comes to understand.
One idea could be a story where Chase has to save Adam from a new villain in the city. Maybe this villain has a special device that can neutralize Adam's powers, and Chase uses his intelligence to outwit the bad guy.
Perhaps Adam has a special power that could either help or hinder Charlie's plans for the hotel. They could go on an adventure together to find a way to use his power for good. Along the way, they face various challenges that force them to rely on each other. This shared experience brings them closer and they start to fall in love as they realize how much they mean to one another.
The contrast between their personalities. Beetlejuice is brash and unpredictable while Adam is calm and gentle. This contrast creates a lot of room for interesting interactions and character development in fanfiction.
One idea could be a Pokemon musical where trainers from different regions compete not just with their Pokemon in battles but also in musical performances. Their Pokemon could have special moves that create musical notes or rhythms in the battle arena. For example, Pikachu could use its electric attacks to create a staccato rhythm.