"It’s— gods, Draco the book itself felt like a Horcrux," she whispered. "Full of this oily and viscous magic that gave me nightmares for weeks. I didn’t even know if it would work—" Hermione bit herself off with a derisive scoff. "It wasn’t like I could test the bloody thing beforehand. But the creator had detailed notes on the scope of the magic and how to control it, examples of the potential for such an insidious spell scrawled in the margins. How to disappear anyone from political adversaries to the occasional, pesky, too-smart-for-their-own-good Muggle-born."