At least some content in this article is derived from information featured in Harry Potter: Hogwarts Mystery. Spoilers will be present within the article.
The Black Lake incident occurred at some point during the 1987–1988 school year, when one of the students at the Hogwarts School of Witchcraft and Wizardry began flying over the Great Lake and repeatedly dived into the water. After this, Headmaster Albus Dumbledore decided that no Hogwarts School brooms should be borrowed to students outside of flying class.
Shortly after the Black Lake incident, Jacob's sibling, who wanted to use a broomstick to fly into the Forbidden Forest in search of the next Cursed Vault, hoping it would lead them to their long lost brother, approached Madam Hooch and asked to borrow a broom. Suspicious, the flying instructor informed them about both the incident as well as Professor Dumbledore's strict instruction for students not to be allowed to use the school brooms unsupervised. She then proceeded to inquire as to the reason they wanted to borrow the broom. She refused to lend them a broom due to Dumbledore's instruction.
Behind the scenes
- In Harry Potter: Hogwarts Mystery, when Madam Hooch inquires why the player wanted to borrow the broom, the player can either tell the truth or lie that they wanted to practise flying so that they could join the Quidditch team of their House. If picking to lie, Madam Hooch would not fall for the bluff, stating that she suspected that they were not being completely honest with her and, that while she had no proof of this, they count themselves lucky if she never obtain any.
- Jacob's sibling, after learning of the incident, thought Tulip Karasu was the student in question, who wished she were, but wasn't and thought the student to be Nymphadora Tonks, who also denied, stating there'd be no chance of her flying over the lake, due to the Giant Squid.
- Jacob's sibling was tricked by Patricia Rakepick into retrieving a key covered in gillyweed from Room 234-00 at Hogwarts Castle, which she needed for her own search. This indicates that there is a Cursed Vaults in the Black Lake, and that there might be some correlation between it and this incident.
- Harry Potter: Hogwarts Mystery (First mentioned)