"I'm pretty sure that he's from the past as well, but we're not discounting any possibility. I'm doing an investigation with the house-elves and portraits, but everything indicates that he just appeared," Harry admitted. "People will need to be careful because we don't know what else could come through. As I told Nott, imagine the things that could have been in this school in the last millenium ,things we don't even know that exist." And it was still not what worried him.
He looked at his mother. "If they are like us, it'll be random and nothing that we can predict. They do seem to come in clusters, though. At least that's what happened with us."
He grinned. "Those spiders have been at Hogwarts before. Just don't tell Ron that they are back." He rubbed the back of his neck. "Nott wasn't completely wrong. Our years were eventful. If that's what the magic is concentrating on, we can expect all sorts of things."