Whomping Willow

From UnknowableWiki

The Whomping Willow is a very brutal and violent tree planted in the Hogwarts grounds. It was planted the year the Marauders came to Hogwarts because of Remus Lupin and his monthly transformations (PA18). The Willow hides a secret passage that leads to the Shrieking Shack. There is a way to temporarily freeze the tree: pressing a particular knot renders it harmless for a while.

The Whomping Willow attacks everything and everyone that comes near enough. It nearly kills Harry Potter and Ron Weasley when Arthur Weasley's flying Ford Anglia gets stuck in its branches (CS5). It does, however, break Ron's wand, causing it to do defective spellwork all year long, until he gets a replacement, after the Weasleys won the Daily Prophet Draw (PA1).

The tree also destroys Harry's Nimbus Two Thousand after Dementors attack him during a Quidditch match (PA9).

In the Marauders' era, students often played a game that consisted of trying to get near enough to touch the trunk of the Willow. Davey Gudgeon nearly lost an eye, and students were forbidden to approach it from then on (PA10).