Shrieking Shack

From UnknowableWiki

The Shrieking Shack is an old house in the outskirts of Hogsmeade (PA5). It's believed to be haunted; these rumours, however, are untrue. Remus Lupin used to go there for his monthly transformations while studying at Hogwarts—hence the occasional howling and ominous sounds (PA18).

There is a passageway leading to the Shack from Hogwarts via the Whomping Willow. It was constantly used by the Marauders during their school years. Sirius Black once told Severus Snape how to get past the tree, and the Slytherin was almost murdered by Remus in his wolf form; he would have been, if it weren't for James Potter's timely intervention (PA19).

The Trio uses the passageway once, led by Crookshanks and Sirius (PA17). While at the Shack, Sirius and Remus confront Peter Pettigrew and the extent of the latter's betrayal of the Potters is fully revealed (PA19).