Crookshanks Immobilizes the Whomping Willow

PAGES: 335-336

As Harry and Hermione struggle to find a way through the Whomping Willow's dangerous branches to rescue Ron, Crookshanks unexpectedly presses a knot at the base of the tree, causing it to stop moving. This allows them to safely approach the tree and enter the gap where the dog had dragged Ron.