“It will not come as a surprise to many of you that there are other worlds besides our own,” he began. “This is not conjecture, it is fact. I have never been to these worlds, and you will never go there. The art of passing between worlds is an area of magic about which very little is known. But we do know that some of these worlds are inhabited.

“Probably the beast we met today was physically quite vast.” (“The Beast” was what Fogg called the thing in the gray suit, and afterward nobody ever referred to it any other way.) “What we saw would have been a small part of it, an extremity it chose to push into our sphere of being, like a toddler groping around in a tide pool. Such phenomena have been observed before. They are known in the literature as Excrescences.

“Its motivations are difficult to guess.” He sighed heavily. “To such beings we look like swimmers paddling timidly across the surface of their world, silhouetted against the light from above, sometimes diving a little below the surface but never going very deep. Ordinarily they pay no attention to us. Unfortunately something about Professor March’s incantation today caught the Beast’s attention. I understand it may have been corrupted or interrupted in some way. That error offered the Beast an opportunity to enter our world.”

At this Quentin convulsed inwardly but kept his face composed. It had been him. He had done it. Fogg went on.

“The Beast spiraled up out of the depths, like a deep-water shark intent on seizing a swimmer from below. Its motivations are impossible to imagine, but it did appear as if it was looking for something, or someone. I do not know whether it found what it was looking for. We may never know.”

Ordinarily Fogg projected an air of certainty and confidence, tempered by his natural slight ridiculousness, but that night he looked disoriented. He lost his train of thought. He fingered his tie.

“The incident is finished now. The students who witnessed the incident will all be examined, medically and magically, and then cleansed in case the Beast has marked or tagged or tainted them. Tomorrow’s classes are canceled.”

He stopped there and left the room abruptly. Everybody had thought he would say more.