In this fanfic, Dumbledore might de - age Harry to give him a second chance at childhood. Harry had a tough childhood, and Dumbledore could think that by de - aging him, he can give Harry a chance to experience a more normal and happy childhood. This would lead to a lot of character development as Harry would have to deal with his past traumas while being in a child's body, and he might also discover new things about his magic along the way.
With Hermione and Ron, it would be very different. If Harry is de - aged, they might see him as a younger, more vulnerable friend. Hermione could become even more protective, like an older sister. Ron might be a bit confused at first but would probably still be his loyal friend. Their dynamic would shift from equals to something more like Harry being the 'little one' they need to look after.
There's also a chance that Dumbledore gets caught by a group of rogue magical creatures. For instance, if he was exploring an area that was supposed to be off - limits to wizards and the creatures there saw him as an intruder. They might not be as rational as wizards and could hold him captive without really understanding who he is.
Well, it could be that Dumbledore has some sort of hidden device or spell that he activates when kidnapped. For example, he could have a charmed object that sends a signal to his allies, like the Order of the Phoenix. His allies then come to his rescue and he manages to escape during the chaos. Also, Dumbledore is extremely intelligent. He might outwit Grindelwald by engaging him in a complex conversation full of riddles and misdirections, which gives him an opportunity to break free.
It could be Severus Snape. He has a complex relationship with Dumbledore. Maybe Snape discovers some of Dumbledore's plans that he doesn't agree with regarding Harry Potter. He then sends a Howler in a fit of anger to express his disapproval.
In a fanfiction, Dumbledore might steal out of desperation. Suppose there was a situation where a curse was about to be unleashed on Hogwarts, and the only way to stop it was by stealing a particular ingredient for an antidote from a place where it was not supposed to be taken. Dumbledore, seeing no other option, decides to steal it. His motive here is to save the school and its students, even if it means breaking the rules.
Fred and George Weasley are very likely candidates. They are known for their love of pranks and their mischievous nature. They might see pranking Dumbledore as the ultimate challenge.
The Riddle Encyclopedia was a resource that collected a large number of riddles and their answers. It could provide various types of riddles, including word riddles, idiom riddles, animal riddles, and so on. This resource could satisfy people's needs for riddles, providing entertainment and intellectual challenges. The specific riddles and answers could be found in the riddle encyclopedia.
Dumbledore, as Harry's guardian in the fanfiction, would probably use his influence in the wizarding world. He could make sure that Harry is taught by the best teachers at Hogwarts. He'd also be there to offer advice and guidance, especially when Harry faces challenges like dealing with Voldemort or other dark forces. For example, he might teach Harry some advanced defensive magic privately to better protect himself.
Well, in some fanfictions, Harry might attack Dumbledore if he discovers that Dumbledore has been using him as a pawn in a bigger game all along. This feeling of betrayal could drive him to lash out. Also, if there is a prophecy that he misinterprets to mean Dumbledore is a threat to his future or the future of his friends, that could be a motive.