In certain fanfictions, Harry could get out of trouble with Umbridge through the power of truth - telling spells. He might be able to prove his innocence by using a spell that forces the truth to be revealed. Also, there could be instances where magical creatures come to his aid. For example, if he has befriended some of the magical creatures on the grounds, they could cause a commotion that diverts Umbridge's attention long enough for Harry to get away. Maybe a group of pixies start causing chaos in her office, and while she's trying to deal with them, Harry slips away unnoticed.
Often, in fanfic, Harry gets out of trouble with Umbridge by having allies. His friends from Gryffindor or other houses could band together. They could create a well - coordinated plan. For example, they might stage a false emergency in another part of the school. Umbridge, being the person in charge of discipline, would have to go and deal with it. This gives Harry the chance to escape. Or his friends could use spells to make it seem like Harry is in a different location while he actually slips away.
One possible consequence could be that she gets fired from her position. If Harry manages to expose her actions, the wizarding school or the Ministry of Magic might not tolerate such blatant abuse of power and take disciplinary action against her.
Hermione is a must. Her intelligence and extensive knowledge of magic and Hogwarts rules would be invaluable. Ron would be involved too. He's Harry's close friend and has a bit of a mischievous streak himself. Fred and George Weasley are very likely to be part of it. They are known for their love of pranks and their dislike of authority figures like Umbridge. Luna Lovegood could also be included. She has a unique perspective and might come up with some really out - of - the - box ideas for Harry's revenge on Umbridge. Plus, her presence would add an interesting and somewhat dreamy element to the whole revenge plot.
In the context of the original Harry Potter story, it seems quite abnormal as Umbridge is a very unlikable character to Harry. But in the world of fanfic, anything can happen. Fanfic allows for different interpretations and character developments, so while it's not normal in the traditional sense, it's possible within the creative space of fan - created stories.
Another way Harry could respond is with a sense of shock and disbelief at first. Given that Umbridge is supposed to be in a position of authority, Harry might be momentarily stunned that she would go to such lengths. However, his Gryffindor courage would soon kick in, and he would likely start to resist, perhaps by using his magic in creative ways to protect himself or to disarm Umbridge, all while trying to uphold the values of the wizarding world that oppose such cruel and unjust treatment.
His friends like Ron and Hermione would surely be there to assist him. Ron could use his strategic thinking and Hermione her vast knowledge of magic. They might come up with a plan to expose Umbridge's wrongdoings which would lead to her being kicked out. Also, the Weasley twins could play a big role. They are known for their pranks and could use their creativity to make Umbridge's life at Hogwarts so miserable that she'd have no choice but to leave. And Dumbledore, even if he has to be a bit more subtle in his actions, could give Harry some guidance behind the scenes.
Snape could face some backlash from the Ministry. If they find out that he was involved in getting rid of Umbridge, they might try to find ways to punish him or at least keep a closer eye on him. However, his skills at subterfuge would likely help him avoid any serious consequences.
In some fanfictions, Harry might use his magic skills in a creative way to embarrass Umbridge. For example, he could make her signature pink outfits turn into ridiculous colors every time she tries to be authoritative. Another scenario could be that Harry reveals some of Umbridge's darkest secrets in front of the whole school, which would surely be a form of revenge as she values her reputation so much.
In some fanfictions, Harry discovers a long - forgotten magic charm that has the power to make a person's worst nightmares come true. He uses it on Umbridge, and she is so terrified by the nightmares that she runs away from Hogwarts. The charm could be something that is based on the person's deep - seated fears, and for Umbridge, it might be related to losing her power and being publicly shamed.