William's dreaming mind finally established that this was no ordinary cauldron, and he took the next logical step. Boggarts lived in cupboards, after all, and this one was certainly preying on his anxiety, if not outright fear. His wand appeared in his hand, and he pointed it with a relatively steady hand at the cauldron. "Riddikulus," he cast, but the cauldron remained unchanged, no matter how hard he willed it to roller skate or emit bubbling red hearts. "Riddikulus. Riddikulus!"
He was sure, with that certainty dreams always brought, that this was a boggart. Which could only mean...he'd lost his magic. And he knew where. He'd replayed it in his mind repeatedly, trying to remember the details, but it was all so hazy, like something out of...
Something out of a dream.
"I need you to see something," he said urgently, turning to Joe and grasping at his robe. He was still gripped with fear by the cauldron-boggart, his skin chilled and goosebumps rising on his arms, but he thought he could do this. He was more aware of dreaming with Joe here, more conscious of the fact that this was a dream. Maybe Joe would be able to see what he couldn't.
There was a panther stepping out of a nearby portrait-frame; they needed to leave now. "Come with me," he pleaded, and around them, the ballroom started to fade, shadows deepening into something more sinister. He could hear the piano starting to play again, drawing him away into the dark.