It could be rival students from Hogwarts who are jealous of their magical abilities. There are always some students who might be envious and could turn to the dark side of magic to try and harm them.
Another possibility is that they are attacked by a group of dark wizards who are trying to make a name for themselves. They might target Snape and Lily because they are known to be talented wizards and witches, and attacking them would give these dark wizards a certain level of notoriety.
Well, if Snape and Lily get attacked in a fanfiction, it could be that Voldemort himself is behind the attack. Snape would be extremely determined to keep Lily safe. He might sacrifice his own well - being to ensure her survival. Lily would be scared but also brave. Maybe she manages to send out a distress signal using her wand, and help arrives just in time to save them both. This could be a turning point in Snape's decision - making regarding his future allegiances.
It could be rogue ninjas from other villages. These ninjas might be jealous of Naruto's power or they could be on a mission to steal some of his unique abilities. For instance, some might want to take the Nine - Tails' chakra from him.
Dumbledore might come to Snape's aid. Dumbledore always had a somewhat complex relationship with Snape, and he would likely step in to prevent things from getting too out of hand. He could use his powerful magic to stop Hermione and then try to sort out the situation calmly.
It could be a group of out - of - town bounty hunters. They might have heard about Nicole's reputation as a tough cop and see her as a valuable target to bring in for some kind of reward. Maybe they are working for a shadowy figure who wants Nicole out of the way so they can take over the town's law enforcement.
It could be Death Eaters who see Hermione as a threat to their new plans. Since she's very intelligent and has been involved in many battles against the dark side, they might target her to send a message to the Order of the Phoenix.
If Snape and Lily were attacked by the Marauders in fanfiction, it could go in many directions. One possibility is that Sirius Black, being the more impulsive of the Marauders, might be the instigator. Remus Lupin, however, might try to hold the others back. In the chaos, Snape could use some dark magic in his desperation to protect Lily, which would have long - term implications for his character. Lily could end up using her charm and intelligence to try to defuse the situation, but if it fails, it could be a tragic event that changes the entire trajectory of their relationships and the future of the wizarding world as they knew it.
The relationship could become more complex. On one hand, Snape would feel a stronger sense of obligation to protect Lily. This might make Lily feel a bit smothered. On the other hand, she would be grateful for his protection during the attack. But she might also be conflicted because she was friends with some of the Marauders too. This could lead to some tension between her and Snape as they deal with their different views on the Marauders.
Harry Potter could visit Snape in the hospital. Despite their past differences, Harry might feel a sense of obligation or curiosity. He could be there to finally have an honest conversation with Snape and perhaps gain a better understanding of his actions throughout the years.
Another character who has a personal vendetta against Clary or her family. For example, a jealous rival or someone who blames her family for past misfortunes. This would add a layer of drama and personal conflict to the fanfiction.
Snape might be initially in shock. He had trusted Lily deeply, so the betrayal would hit him hard. He could become very angry and bitter, perhaps vowing revenge against her. He might also close himself off emotionally, not wanting to trust anyone again.