Disclaimer: Credits to J.K. Rowling. Well, the story is mine but the characters are hers.
The Whomping Willow had been lonely for quite some time now.
In the beginning, it'd had the little boy who came down once a month accompanied by his nurse. The tree heard his suffering every full moon.
Then the boy had gotten friends to keep him company as animals. The tree watched them play, bathed in moonlight.
There had been another boy, once, who went in the tunnel before promptly running back out. The tree expected to never see him again.
Of course, the Willow saw the other children outside but they never came close to it. Only some of the teachers ventured near it, though never within its reach.
For years and years, it watched from afar, the monotony only broken by a car crashing into it and the Willow could have sworn it'd gotten one of its boys back: the one with messy hair.
Some time later, the werewolf came back, a grown man. The tree heard his misery every full moon.
Later came two others: one as a dog and one as a rat along with three children, two of whom it recognized. The tree watched them fight, bathed in moonlight.
Then came a snake man followed by another of its first boys, the one it'd only seen once. He too was a grown man now. The tree never saw him again.