In the 'harry attacks lily fanfic', perhaps it's a scenario where the normal boundaries of the Harry Potter universe are broken. It could be due to a time - travel mishap where Harry's actions are out of place and he ends up attacking Lily. Or it could be a case of some evil entity controlling Harry to carry out this unthinkable act against his mother - like figure, Lily.
I'm not aware if it's a popular fanfic. There are so many fanfics out there, and this one with such a controversial premise might not be mainstream. It could be a niche creation that only a small group of fans who are interested in exploring extreme and unorthodox storylines might know about.
Since this is a fan - created concept that goes against the fundamental relationships in the 'Harry Potter' world, it's hard to define what a specific fanfic like this would be about. Fanfics should generally stay within the boundaries of the original world's ethics and relationships.
In some fanfics, it could be due to a threat she believes she can't protect Harry from. Maybe she thinks that by leaving him, the dark forces won't target him as much.
In this kind of fanfic, perhaps Harry has finally had enough of the Dursleys' mistreatment. He might use his magic in a moment of rage. Maybe he starts by levitating Dudley to teach him a lesson after one too many taunts. Or he could use a spell to make Aunt Petunia's precious china smash, as a way of getting back at her for all the years of neglect and cruelty.
Well, it could be about Lily Potter, Harry's mother, in a fictional scenario where she desires to have Harry back. Maybe it involves some sort of magic or alternate reality where she gets a chance to be reunited with him. It might explore her emotions, like the longing and love she has for her son that was taken away from her so early.
One great fanfic could be 'Harry and Lily's Enchanted Bond'. In this story, Lily, being a fairy, might use her magical fairy abilities to help Harry in his adventures at Hogwarts. It could add a whole new dimension to the wizarding world as we know it.
One possible fanfic could be about Lily Luna Potter discovering a magical lemon tree in the Hogwarts grounds. The lemon might have special properties that are tied to her family's legacy. For example, it could produce lemons that when squeezed, release a potion - like liquid that can cure common wizarding ailments. She then has to protect the tree from those who would use its power for dark purposes.
In some fanfics, James and Lily giving Harry away might be due to a prophecy that requires Harry to be raised away from them for a certain power to develop. So they make the heart - wrenching decision to give him to a family that has some special connection to an ancient magic that can safeguard him.
Perhaps in this fanfic, Harry has been influenced by dark magic or some evil entity. This external influence could distort his perception of Lily and turn his normal feelings for her into hatred. Dark magic has the power to corrupt one's mind and change relationships in unexpected ways.
In the fanfic, Lily's fairy heritage could make her a target for dark forces. Harry, being the hero he is, would then vow to protect her. Their relationship would grow as they face numerous challenges together, and Harry might learn some new spells or techniques from Lily's fairy magic along the way. This would not only strengthen their bond but also make Harry a more powerful wizard.