I'm not sure of a specific fanfiction with this exact plot, but you could try searching on popular fanfiction platforms like Archive of Our Own. Use the tags 'Snape', 'deaged', 'Lucius' and '16' to narrow down your search.
Maybe Lucius deages Snape out of jealousy. Snape was always a bit of a rival in Voldemort's eyes. In his deaged state, Snape might form unexpected friendships with students at Hogwarts. He could befriend Hermione, for example, who would be intrigued by this strange new version of Snape. Meanwhile, Lucius has to keep his actions a secret from Voldemort, as Voldemort might not be happy with his meddling in Snape's life.
It could be that Lucius accidentally deages Snape while trying out a new, experimental spell. Then, the story could revolve around how Snape has to deal with being 16 again in a world that has moved on. He might struggle with his memories of the future and how to interact with people who knew him as an adult. For example, he'd have to face his former students who are now his peers, and that could create some really interesting and complex situations in the fanfiction.
Snape's deaged personality could also be more impulsive. Without the restraint of his adult self, he might act on his emotions more quickly. For example, if he felt wronged, he might lash out immediately instead of plotting a long - term revenge like his older self would do. Also, he could be more curious about the world around him, eager to explore magic in a new way that his older self had forgotten due to years of being jaded.
Snape and Lucius can be presented in various ways in fanfiction. One common portrayal is that Lucius, being from a wealthy and influential pure - blood family, may look down on Snape at first due to Snape's half - blood status. But as they grow older, they find common ground in their service to Voldemort (although Snape has his own hidden motives). Their relationship might be full of intrigue and hidden agendas.
In deaged Snape fanfiction, the theme of redemption can be quite prominent. It gives Snape a chance to rewrite some of his past actions or at least be seen in a new light. There's also the theme of identity crisis. He's not the same old Snape, and he has to figure out where he fits now. Additionally, the theme of adaptation is common. He has to adapt to his new physical state, new social situations, and new magical abilities or limitations that come with being deaged.
There's also 'Hermione's Second Childhood with Snape'. It's a unique take on the concept. The story shows how Hermione's deaging affects not only her relationship with Snape but also how she views the wizarding world all over again. The author creates a lot of heart - warming and sometimes tense moments between the two characters as they navigate this strange new situation.
The relationship between Snape and Lucius in fanfiction is significant as it can shed light on the darker side of the wizarding world. It can show the inner workings of the Death Eaters and how loyalty and power are intertwined. For instance, Lucius might use Snape's position at Hogwarts for his own ends, or Snape could be using Lucius to maintain his cover.
In fanfiction, the relationship between Snape, Hermione, and Lucius can be very complex. Snape is often a multi - faceted character. He has his own hidden motives and a deep backstory. Hermione, being the intelligent and strong - willed witch she is, can interact with Snape in various ways. Lucius, on the other hand, is a more villainous character. In some fanfictions, Hermione might find herself in the middle of the power struggle or hidden agendas between Snape and Lucius. For example, a fanfiction could explore how Hermione's knowledge and skills influence the relationship between Snape, who has a long - standing grudge against the Malfoys, and Lucius, who is always looking for ways to gain more power in the wizarding world.
Snape, Hermione and Lucius interact in really interesting ways in fanfiction. Snape might initially be distrustful of Hermione due to her friendship with Harry, but then come to respect her intelligence. Lucius, being a Death Eater, could see Hermione as a target or a means to an end. In some fanfictions, Snape has to protect Hermione from Lucius' schemes. It's all about how the author wants to twist the relationships between these very different characters.