People put a great deal of thought into doors, like the vaults in Muggle banks. But for wizards, an Alohomora was enough to open them. Scamander had done exactly that back in New York, though his purpose had been to catch a Niffler that had run into a bank vault.
The doors of Gringotts vaults were far more complicated. Some could only be opened with Goblin magic. Harry Potter had seen this on his first day back in the Wizarding World, when Hagrid took him to Vault 713 to retrieve the Philosopher's Stone.
In 1993, after news of Sirius Black's escape spread, Hogwarts further strengthened its security measures. Flitwick taught Hogwarts' Qianmen how to "recognize" Sirius, who had just escaped from Azkaban, from his wanted poster.
Anyone who had seen Hogwarts' Qianmen would be amazed, but even more astonishing was that Flitwick had actually taught a door to recognize people. Of course, none of that was the point.
"If I were you, I wouldn't touch it." Pomona, draped in a black cloak, "kindly" reminded Snape, "I thought you'd lived in the Wizarding World for many years, Severus."
At that moment, the Slytherin Head's hand was about to touch a snake-shaped door handle mounted on the Black family's peeling black wooden door.
"It's just an anti-Muggle door handle," Severus said casually, then firmly placed his hand on it.
The Qianmen actually opened, and Severus was unharmed. Pomona followed him inside. The courtyard looked even worse than the front entrance. It had been neglected for many years and looked as though it had long been abandoned.
Pomona looked around nervously, hoping Sirius would not return to the old house at Grimmauld Place at this moment.
Yet after entering, Severus did not continue inside, as though he were "sensing" something.
"There's something alive