"You think it appeared on a schedule? A belated effect of the holiday decoration charm?" That was an explanation he hadn't considered. It made sense, though, since the charm had gone awry in nearly every other particular.
He walked up to where Spencer stood, joining him in staring up at the ceiling. "I was worried that it might be cursed. Creeping around on its own, or manifesting, or something. I would have noticed if someone had hung it up there." At least, he was nearly certain he would have. It had been quiet in the library today; he'd only been away from his desk once or twice, and there hadn't been many students about. He examined it again with Spencer's evaluation in mind, shoulders drooping slightly, and admitted, "I suppose yours is a much more logical explanation."