Well, it could be that the Marauders find baby Severus in some sort of difficult situation. Maybe his parents are unable to take care of him for a while. So, they take on the role of caretakers. They might struggle at first because they have their own pranks and chaos, but gradually learn to be responsible.
It could be Remus. He is the most level - headed of the group. He would be patient and understanding with a baby. His calm nature would be well - suited for taking care of baby Severus.
One possible plot could be that the Marauders, in some magical time - travel or alternate reality scenario, get to meet baby Harry. They might be overjoyed to see him and immediately vow to protect him. Sirius could be especially attached, given his future relationship with Harry. They might also play with baby Harry, making him giggle with their magic tricks.
One possible plot could be Severus saving baby Draco from a dangerous situation. Maybe there's a dark wizard targeting the Malfoy family and Severus steps in to protect Draco. This could start a special connection between them.
One possible plot twist could be that the Slytherins, who are often seen as the 'bad guys' in the Harry Potter universe, discover a prophecy related to Harry while taking care of him. This prophecy might not be the same as the one in the original story and could lead them to protect Harry in a way that goes against their traditional Slytherin values. For example, they might have to form alliances with Gryffindors or other houses they usually oppose.
Perhaps in the fanfiction, a powerful magical artifact forces Harry and Severus to conceive a baby as part of a prophecy. They initially resist but gradually come to accept it. The plot might involve their journey to protect the baby from dark forces who want to use the baby's unique heritage for evil purposes. They have to put aside their differences and work together as parents.
In this fanfiction, Severus might adopt Harry to protect him from the dark forces that are still lurking around. He would use his knowledge of the dark arts and potions to keep Harry safe. He could also introduce Harry to a different side of the wizarding world, one that is more about academic study and self - discovery. For example, he may encourage Harry to study advanced potions at a very young age, which would give Harry an edge in his future magical education.
One possible plot could be that in a post - war world where things are turned upside down, Hermione discovers baby Draco alone and abandoned. She decides to take him in out of her sense of justice and kindness. She might struggle at first, trying to understand his needs as a baby Malfoy, but gradually, as she takes care of him, she starts to see the potential for change in him. Draco, as he grows up under Hermione's care, could start to develop different values than what he was taught in his pure - blood family.
One possible plot could be that Harry discovers a time - traveling accident has brought baby Snape to his present. Harry, being the kind - hearted person he is, takes it upon himself to care for the baby. He has to figure out how to feed the baby, keep him clean and comfortable. Maybe he also has to protect baby Snape from any threats in the wizarding world that might target Snape even as a baby.
One possibility could be that Draco is forced into taking care of Harry due to some magical circumstances. Maybe there's a spell gone wrong that makes it his responsibility. He initially resents it but as he spends time with baby Harry, he starts to see the innocence in him and develops a soft spot.
Perhaps the baby's existence causes a rift in the wizarding world. Some might view it as an abomination due to the age and past relationship between Hermione and Severus. This could lead to Hermione and Severus having to fight not only for their baby's safety but also for their right to be a family in a world full of prejudice.