The Diary lay quietly on his bed, as if it had been there all along, untouched.
Will snatched up the Wand beside his bed and pointed it at the Diary. His Silver-Gray Eyes flickered. Through the Sight of the Wizard's Eye, he saw that the Magic patterns on the Diary had entered a new stage.
After getting the Diary, Will had divided its development into stages based on its Magic patterns and the amount of Magic it held.
After all, in the original timeline, the Diary had changed noticeably several times after Ginny got it. At first, it could only talk to her, but later it could manifest. From the outside, the stages were the confidant Diary stage, when it talked with Ginny; the body-control stage, when it made her release the Basilisk; and the manifestation stage. How its Magic changed along the way was anyone's guess.
In Will's hands, the Diary had already gone through two stages, but in both, it had only stolen his Magic. It had shown no sign of trying to control him.
Will had called the first stage, when almost no Magic was visible, the dormant stage. That was a Horcrux's usual state: lying dormant and waiting for its chance. He called the second stage the confidant Diary stage, and he had wrung quite a bit out of the Diary during it.
Now the Diary could move on its own, climb onto his bed, and display a stage of Magic he had never seen before.
His Wand moved. "Sectumsempra!"
An invisible blade struck the Diary without leaving a mark. Will was not surprised. Every Horcrux was protected by powerful Dark Magic cast by Voldemort. Ordinary spells and methods could not destroy one.
The Diary opened by itself, though there was no breeze. A line appeared