In some fanfictions, the Whomping Willow might be a sentient being that has a special connection with Sirius Black. Maybe it was enchanted by a powerful wizard long ago, and only Sirius, with his unique magical aura, can communicate with it. This could lead to a plot where Sirius enlists the help of the Whomping Willow to defeat a common enemy, like a group of dark wizards who are after Hogwarts.
Often, Sirius Black interacts with the Whomping Willow in a very brave and sometimes reckless way in fanfiction. He might just charge at it, using his quick reflexes to avoid getting hit while he tries to access the secret passage it guards. His interactions are usually driven by his need to get in or out of Hogwarts secretly.
One interesting story could be where Hermione discovers a hidden passage near the Whomping Willow. She uses her intelligence to figure out how to get past the tree's violent branches without getting hurt. Maybe she uses a spell she's been researching in secret.
In some fanfictions, there might be a plot where a student gets trapped under the Whomping Willow during a full moon and has to be rescued by a werewolf, creating a complex and dangerous situation that tests the relationships between different characters in the wizarding world. The Whomping Willow could also be a central part of a mystery, for example, it might be the key to unlocking a secret about Hogwarts' founding or a long - lost treasure. Characters would then have to figure out how to interact with the dangerous tree without getting seriously injured to solve the mystery.
Another aspect could be the relationship between the Whomping Willow and the characters we know. For instance, perhaps Fred and George Weasley once tried to prank the tree and had a hilarious yet dangerous encounter. Or Hermione might study the tree in her quest for knowledge, trying to find out more about its magical properties and how it fits into the overall ecosystem of Hogwarts.
Well, one possible plot could be Sirius seeking revenge on the Death Eaters who wronged him. He might use his Animagus form to spy on them and then plan elaborate traps. Another could be his revenge on those who framed him for the crimes he didn't commit, like using his intelligence to expose their lies in a very public and embarrassing way.
One common theme is danger. The Whomping Willow is a dangerous entity in the Harry Potter world, so many fanfictions play on that. Writers might create scenarios where characters are in peril because of the tree's violent movements.
One idea could be the Whomping Willow as a guardian of a hidden Hogwarts garden. In this fan fiction, the tree only allows those with pure hearts to pass through its branches to reach the beautiful and enchanted garden filled with rare magical plants. It could be a story of discovery for young students.
One interesting plot is when Harry discovers a hidden prophecy about Sirius Black that leads him on a dangerous quest to uncover the truth. Another is when Harry suspects Sirius of being involved in a dark magic plot and has to spy on him secretly. There are also stories where Harry and Sirius team up to investigate an ancient mystery within the wizarding world that has been long forgotten.
In this fanfiction, perhaps Harry is trying to tame the Whomping Willow. He might be on a mission to protect his friends from the dangerous tree and in the process, forms an unexpected bond with it. He could be using his skills and courage to face the challenges the tree presents.
She could play the role of a problem - solver. For instance, if the Whomping Willow is causing trouble in the Hogwarts grounds by attacking students more often than usual, Hermione might step in. She'd study the tree's behavior, look into old Hogwarts records about it, and come up with a solution to calm it down, like a special potion or a modified spell.