Well, it could be that Pennywise and the Joker are both manifestations of some greater evil force in this fanfiction. They initially see each other as rivals, but then realize that by combining their powers, they can create a much more nightmarish scenario. They begin to target children first, as Pennywise is known for that, and the Joker enjoys the chaos and despair it brings. The heroes then have to figure out how to separate them and defeat them.
The Joker would probably be more dominant in terms of manipulation. He's a master of psychological warfare and could easily manipulate Pennywise into doing his bidding. For example, he could play on Pennywise's need for fear and chaos, and direct it towards his own goals in Gotham.
One possible plot could be that the Joker discovers he has a daughter he never knew about. At first, he might be skeptical or even angry. But as he spends time with her, he starts to feel a strange sense of protectiveness. He tries to keep her away from his criminal life, but his enemies find out about her and then he has to fight to keep her safe.
Well, it could be about Batman trying to stop the Flashpoint Joker from causing chaos in Gotham. Maybe the Joker has a new and devious plan that only Batman can foil.
In the 'georgie meets pennywise fanfiction', it's possible that Georgie is not alone when he meets Pennywise. Maybe he has a friend or an older sibling nearby. They could try to protect Georgie from Pennywise. Pennywise, on the other hand, would use his powers of illusion to try and separate Georgie from his protector. Georgie's innocence might be his strength in this encounter, as he could see through some of Pennywise's tricks more easily than an adult. Also, the setting could play a big role. If it's in a dark alley or a deserted place, it would add to the overall sense of dread and danger.
Well, perhaps the plot could revolve around Bruce's struggle to contain the chaos the Flash Point Joker brings. The Joker might be causing mayhem in a way that's different from the regular Joker. Bruce has to adapt his strategies, and in the process, he might learn some dark secrets about his own city or himself. It could also involve a psychological battle as Bruce tries to outwit the unpredictable Flash Point Joker.
The plot might involve a character being lured into Pennywise's lair, perhaps by the allure of missing things or people. Pennywise could use his shape - shifting abilities to deceive the kidnapped character throughout their captivity.
One interesting plot could be that the Joker somehow gets hold of the tailed beasts' power. He then uses this power in his own twisted way, creating a new kind of threat in the Naruto world. This would force the ninja to not only fight against his physical strength but also his unpredictable and crazy nature. The story could then focus on how the ninja, led by Naruto, try to outwit the Joker and regain the tailed beasts' power.
Perhaps the Joker discovers a way to mind - control some of the Avengers. He targets Hulk first, making him go on a rampage in a major city. The other Avengers are caught off - guard. They soon realize it's the Joker's doing. Spider - Man, who has recently joined the Avengers, swings in to help. He uses his agility to dodge the Hulk's attacks and tries to figure out a way to break the mind - control. Doctor Strange is called in to use his magic to counter the Joker's mind - games, and the team must fight both the controlled Avengers and the Joker's minions to save the day.
Well, it could be a total chaos. Harry Potter's magical world is all about order in a way, with Hogwarts rules and the fight between good and evil in a more traditional sense. The Joker, on the other hand, is the agent of anarchy. Maybe he'd start causing mayhem in Hogwarts, like turning the moving staircases into death traps or making the portraits go berserk. And Harry would have to use his magic in really unorthodox ways to stop him.
Another idea is that Pennywise's pregnancy is the result of some sort of dark magic or a pact with an even more sinister force. The fanfiction could explore how Pennywise navigates this new situation, whether it tries to hide it from its usual prey or uses it as a weapon. For example, it could pretend to be a vulnerable pregnant entity to lure in those with a sympathetic nature, only to reveal its true self at the last moment.