The defenestration spell could be incorporated as a key plot device. For instance, if there's a mystery about a series of 'window - related' incidents in Hogwarts, and Harry suspects the defenestration spell is involved. He then starts to investigate who might be using it and for what purpose.
You could incorporate the defenestration spell into a Harry Potter fanfic by having it be a spell that is only known to a certain group of wizards. Harry finds out about this group and their special spell when he witnesses a strange event where someone is defenestrated in a very unusual way. He then tries to infiltrate the group to learn more about the spell, its limitations, and its potential uses. This could lead to a story full of mystery, adventure, and self - discovery for Harry.
A great concept for a Harry defenestration spell fanfic would be to create a whole new adventure around the spell. Harry could be on a quest to find the true meaning and full power of the spell. Along the way, he meets different characters, some who are trying to stop him from uncovering the spell's secrets and others who want to help. This could lead to a lot of exciting plot twists and character development.
You could make the succubus drain be part of a curse that was placed on Hogwarts long ago. Maybe it was put there by a dark wizard who wanted to weaken the school's magic. In the fanfic, the characters start noticing that students are getting weaker and tired all the time. They then discover the source is a succubus draining their energy, and they have to search through old books and magic spells to find a way to break the curse.
One way is to create a new Ministry department that deals with magical taxes. You could write about how this department audits wizarding businesses. For example, Ollivander's wand shop might be audited for taxes on the sales of wands. Another way is to introduce a tax on magical creatures. Hagrid might have to deal with the new tax regulations for his care of magical creatures at Hogwarts.
Well, 'Harry Potter' candy can be used as a plot device in fanfics. For instance, a poisoned candy could be sent to a character, leading to a mystery of who the culprit is. It could also be a way to show friendship, like when a character gives their favorite Honeydukes candy to another as a sign of loyalty.
It could be a reference to a certain character's look or attitude. Maybe there's a new character in the fanfic who has a steely gaze, and the author describes it as 'blue steel' to give a sense of mystery and cold determination. This character could be an ally or an enemy to Harry and his friends, adding a new layer of intrigue to the story.
They can be incorporated as new magical creatures in the Forbidden Forest. Maybe they have their own hidden enclaves there and interact with Hogwarts students who stumble upon them. For instance, a faery hero could offer help to a lost student by using its faery magic to guide them back to the castle.
It could be a magical place that characters from both universes are drawn to. For example, Frodo from 'The Hobbit' might be lured to 'Over the Rainbow' by a strange magic, and there he meets Harry Potter. They then have to work together to return to their respective worlds.
One way is to have it as a guide. For instance, a young wizard or witch could be lost in a forest near Hogwarts, and a blackbird flying overhead could lead them to safety, like to a hidden passage or an old, forgotten hut that holds some important magical item.
Magic wands can be used. The person asking can wave their wand and make a magical display of lights and sparkles that form the words of the promposal. For example, a simple 'Wingardium Leviosa' spell can be used to levitate the promposal sign in front of the person being asked.
The Gorgon could be incorporated as a new threat that emerges from an ancient part of the wizarding world. For example, if a dark wizard discovers a way to control the Gorgon, it could be sent to Hogwarts to cause chaos. Harry would then have to figure out a way to stop it without getting turned to stone.