Well, a common concept could be that the Leviathan is a threat in the fanfiction world. Harry, as an Animagus, might have to use his unique abilities to protect others from the Leviathan. His Animagus form could give him an advantage in speed or stealth. Maybe he can fly closer to the Leviathan in the form of a bird Animagus to study it without being detected. Or if he's a cat - like Animagus, he could use his agility to escape from the Leviathan's attacks while trying to figure out a way to defeat it.
One interesting concept could be Harry Potter's Animagus form interacting with the Leviathan. Maybe his Animagus form is a small creature like a mouse, and it has to find a way to communicate or avoid the Leviathan. Another idea is that the Leviathan has some sort of magical connection to Harry's Animagus ability, like it can sense when he is in that form. Also, perhaps Harry uses his Animagus form to explore a hidden world where the Leviathan resides, and discovers secrets about the wizarding world that were previously unknown.
Perhaps a Basilisk Animagus could have a special connection with the other snakes in the wizarding world. In the story, they could communicate with snakes to gather information. This would give them an edge in situations like uncovering plots within Slytherin house, as the snake is the symbol of Slytherin. They might be able to understand the secrets that the snakes around the Slytherin common room are aware of.
One interesting concept could be a Twilight vampire using Animagus form to avoid detection by wizards. They could transform into small animals like a mouse and hide in the wizarding world unnoticed.
One interesting concept could be characters having multiple animagus forms. For example, a character might be able to transform into a bird and a cat. This could add new layers to the story, like how they use different forms for different tasks or to solve mysteries.
In non - sexual Harry Potter fanfiction, Animagus could be used in various ways. For example, an Animagus character might use their form to spy on Death Eaters. They could transform into small animals like a mouse to sneak into hidden places where important information is stored. Another concept could be using the Animagus form for self - discovery. A character might learn more about their true nature by experiencing life as an animal.
One interesting aspect could be seeing Harry's new form as an Animagus. Maybe he turns into a unique animal that gives him different abilities and perspectives in the wizarding world.
One interesting plotline could be Harry discovering his animagus form earlier than in the original series and using it to secretly explore Hogwarts at night. He might find hidden passages or secrets that were previously unknown.
His Animagus ability might be enhanced. The danger posed by the Leviathan could make Harry more in - tune with his magical side. For example, if his Animagus form is a stag, he might become faster or more powerful in the presence of the Leviathan. It could also be that the Leviathan has a certain magical aura that affects Harry's transformation. Maybe it makes it easier or more difficult depending on the situation.
One interesting concept could be exploring more about the Marauders' time at Hogwarts. Fanfiction might expand on their adventures, like pranks they played that were never mentioned in the original book. Another could be different interpretations of Sirius Black's escape and his relationship with Harry during that time.
Some fanfictions in Harry Potter 2 might play with the idea of the basilisk having different powers or weaknesses. It could also explore the idea of a hidden connection between Ginny and the Chamber of Secrets that goes beyond what was in the original story. There might be fanfictions that change the role of certain characters, like making Neville a more central figure in solving the mystery of the Chamber.
Well, perhaps in the fanfiction, Harry becomes an Animagus to better spy on the Death Eaters. His form could be a small, inconspicuous animal like a mouse or a sparrow. He uses this ability to sneak into their meetings and gather crucial information for the Order of the Phoenix. It could also lead to some humorous situations, like when Hermione almost steps on him not realizing it's Harry in his Animagus form.