In some versions of this fanfiction, the Dursleys might be forced to live in Harry's world for a while. They have to deal with magic all around them, but they don't understand how it works. For example, they might accidentally end up in Diagon Alley and be completely lost and bewildered, with all the strange creatures and wizards looking at them oddly. This would be a huge punishment for them as they have always shunned the magical world that Harry is a part of.
One scenario could be that Dudley gets turned into a frog. It would be a fitting punishment for his years of bullying Harry. Another could be that the Dursleys' house starts to have strange magical malfunctions, like the stairs turning into a slide, constantly tripping them up.
Perhaps in the fanfiction, Vernon's car keeps breaking down in the most embarrassing situations. Every time he tries to drive to work or show off his new car, it just sputters and stops. And Petunia could find that all her precious garden flowers are replaced with weeds overnight, which would drive her crazy as she takes so much pride in her garden.
Often it could be the magical community. Since the Dursleys have mistreated Harry, a wizard, for so long, the Ministry of Magic or some powerful wizards might decide to teach them a lesson. For instance, Dumbledore could use his power and wisdom to make sure they face consequences.
Perhaps Harry is rescued by an unexpected character, like a centaur who has been secretly watching over him. The centaur arrives at the Dursleys' on a moonlit night, and using its natural magic and knowledge of the stars, it convinces Harry to come with it to a safe place in the Forbidden Forest where he can be protected and trained.
One interesting 'marauders get punished fanfiction' could be where they are caught hexing other students in the hallways and are made to clean the entire school library as punishment. It shows a different side of their usually mischievous characters.
One possible scenario could be that the Dursleys, out of their long - held hatred and jealousy, manage to poison Harry's food. In the fanfiction world, they might find a way to obtain a powerful and undetectable poison. Another could be that they stage an 'accident' like a fire in his room while he's asleep. They could block his escape routes and let the fire consume him.
One possible scenario could be that Harry uses his magic skills in a creative way to escape. Maybe he creates a diversion with a spell to distract the Dursleys and then slips away unnoticed. Another could be that he gets help from an unexpected ally, like a friendly magical creature that guides him out of the house.
One possible scenario could be that Harry discovers a hidden magical passageway in his tiny bedroom at the Dursleys'. It could be a secret portal created by a well - meaning wizard long ago to help any oppressed magical being in the Muggle world. Harry stumbles upon it while looking for a lost sock or something mundane. Another scenario might be that a group of friendly magical creatures, like house - elves, conspire to help him escape. They create distractions around the Dursley house, like making the pots and pans fly around and creating chaos, which allows Harry to slip away unnoticed.
One possible scenario could be that Voldemort punishes Harry Potter by using the Cruciatus Curse on him. In the wizarding world, this is a very cruel form of torture. Another situation might be that Voldemort imprisons Harry in a dark and desolate place, like the dungeons of Malfoy Manor. He could also force Harry to watch as he harms his friends, which would be a psychological form of punishment for Harry, who values his friends highly.
Another possibility could be that he is punished for being too reckless in a battle. He might put his teammates in danger, and as a result, face some form of punishment from his comrades or superiors.
In some fanfictions, they might go on a really unique honeymoon. Maybe to a scientific research station in Antarctica where they can study the unique wildlife together. It would be a blend of their love for each other and their passion for science.
In some fanfictions, there might be a scenario where Harry and Ginny get engaged during a dangerous adventure. They could be on a mission to defeat a new dark wizard, and in a moment of calm before the final battle, Harry realizes that he doesn't want to face anything else without Ginny by his side, so he proposes. Or perhaps it happens during a celebration at Hogwarts. After a big victory for the school, like winning the House Cup, Harry takes Ginny to the Astronomy Tower and asks her to marry him. There could also be a situation where Ginny is the one who takes the lead. She might plan a special date and then propose to Harry, showing her strong and independent character.