The Harry Potter series may have ended in 2007, but the world is constantly being expanded with the movie series, the play, and J.K. Rowling’s writings on Pottermore. J.K. Rowling's website has fun quizzes to find out your house, wand, and patronus, but it also has a lot of writing about the Potterverse. If you're a Potterhead and you haven't been reading Pottermore, you're missing out.
1. The sasquatch rebellion
This is mentioned briefly in the history of MACUSA. In 1892 the wizarding world was nearly exposed when Irene Kneedander, Head of the Body for Protection of Magical Species (Humanoid), angered the sasquatch population. Kneedander used her job to bully magical creatures, attacking any sasquatch she felt needed to be put in their place. The sasquatch population descended on Washington to let MACUSA know how they felt about this treatment. After mass Obliviations and extensive damage to MACUSA headquarters, the magical government had to relocate to New York.
2. The Floo Powder accident
In 1855, a British witch named Violet Tillyman had a fight with her husband. She got into the fireplace and, while sobbing, said she wanted to go to her mother’s house. As any Harry Potter fan knows, it’s important to speak clearly when using the Floo Network. Albert Tillyman eventually went to his mother-in-law’s house to get his wife back and discovered she had never arrived at her destination. He never did learn what happened to his wife. Violet resurfaced twenty years later, after Albert’s death. Turns out she wound up at the home of the handsome Myron Otherhaus. For the past twenty years she had lived happily with Myron and their seven children.
3. The Celestina Warbeck incident
Molly Weasley’s favorite singer, Celestina Warbeck, is a Welsh witch known all over the magical world for her singing prowess. Unfortunately, two muggles accidentally wound up at one of her concerts in 2003. The muggles had accidentally stumbled upon a portkey while walking their dogs. One muggle was invited onstage for a duet and, despite being Obliviated, later wrote a song that sounded suspiciously like the one he wasn’t supposed to remember. Warbeck was less than pleased.
4. Uagadou’s animagi
Uagadou is the best wizarding school in all of Africa. Uagadou’s students are well-versed in self-transfiguration and at an International Symposium of Animagi they caused quite a commotion. The school team of animagi performed a synchronized transformation. The other witches and wizards in attendance were not particularly happy about a bunch of teenagers turning into dangerous beasts, such as elephants and cheetahs. Adrian Tutley, a animagus with the ability to turn into a gerbil, even filed a formal complaint.