Another plot idea could be that Harry's shapeshifting causes some confusion among his friends. At first, they don't recognize him when he changes forms, and this leads to some comical and also some tense moments as they try to figure out if it's really him or an imposter.
One idea could be that Harry uses his shapeshifting ability to spy on the Death Eaters unnoticed. He could transform into a small creature like a mouse and infiltrate their meetings.
Maybe Harry discovers his shapeshifting ability is linked to an ancient magic. For example, he finds out that he can transform into mythical creatures from the wizarding world's past only during certain moon phases, which adds an element of mystery and limitation to his power.
One idea could be Harry discovers he has the ability to shift into a powerful magical animal like a phoenix. He could use this form to secretly protect Hogwarts from dark forces at night. Another plot could involve Harry being cursed to randomly shift into different animals until he finds a way to break the curse, leading to some comical and dangerous situations as he tries to adapt to each new form.
One idea could be a pokemon shapeshifter that is trying to hide its true form in a human - dominated city. It has to constantly adapt and learn human behaviors to avoid detection.
One idea could be a dragon shapeshifter who is forced to hide in human form in a modern city. They have to constantly struggle to keep their true identity a secret while also being drawn to other magical beings in the city. Another plot could involve a dragon shapeshifter falling in love with a human, and having to decide whether to reveal their true form or not. Or perhaps a story where a dragon shapeshifter is on a quest to find a lost magical artifact that is crucial for the survival of their dragon clan.
One plot idea could be Ash getting the ability to shapeshift accidentally. For example, he touches a strange Pokemon or an ancient artifact. Then he has to figure out how to control this new power while on his journey to become a Pokemon master. Another idea is that an evil organization wants to use Ash's shapeshifting ability for their own nefarious purposes, so he has to avoid them and protect his friends.
One plot idea could be Percy using his shapeshifting ability to infiltrate the lair of a powerful enemy. He could transform into a small animal like a mouse to get past defenses and then change into a more formidable form to fight. Another could be Percy struggling to control his shapeshifting, accidentally changing forms at inconvenient times, like during a school exam or a tense conversation with his friends.
Perhaps Harry discovers he's a shapeshifter early on in his Hogwarts years. He might use this power to play pranks on the Slytherins by changing into a mouse and scaring them in the dungeons. But then, he realizes he has a greater responsibility when he sees the potential of using it against the Dark Arts. For example, he could shift into a large and powerful animal like a hippogriff to fight off Dementors.
One interesting concept could be a shapeshifter who uses their ability to infiltrate the Death Eaters. They could change their appearance to gather intelligence and help the Order of the Phoenix.
One idea could be a Pokemon that can shapeshift into different legendary Pokemon to gain their powers. For example, it could shift into Mew to use its psychic abilities in unique ways. Another idea is a shapeshifting Pokemon that disguises itself as other common Pokemon to play pranks on trainers. It could be really fun to write about the chaos it causes.
Maybe Harry is the only merman in a world where mermaids are common. He faces discrimination at first but then uses his unique abilities to save the underwater kingdom from a great danger. For example, he might have a special power to purify poisoned waters that the mermaids don't have.
One idea could be that Harry Potter is magically transported to the Avengers' universe. He could use his magic to help the Avengers in battles, like creating protective shields with spells. Another idea is that the Avengers are somehow sent to Hogwarts, and they have to learn about magic while also dealing with threats in the wizarding world. For example, Iron Man might try to figure out how to integrate his technology with magic.