"He may have weighed over thirty stone," he answers with a quirked eyebrow, "but I doubt he was actually made of it."
"Potter was, for a year or so, but he was only, as far as we can make out, really aware of it for about three minutes." He rolls his eyes. "I suppose some would say that it's reasonable that a desire to bite the Headmaster should not have set off his internal alarms, but really."
"No, they were careless and failed to exercise an iota of forethought," he says flatly, and then, insulted, "Of course there were. And Ravenclaws, as well, although he was more like to manipulate Ministry 'Puffs than mark them."
"He was a most unhappy fool," Severus notes, moving over there without haste, ostensibly to fetch the strawberry seeds. "But I suspect he would have used one on Crouch, if he'd been able to bear the understanding that he needed to." He stops very near to Q, just behind his shoulder. "Who, then."
"It's one of those potions that builds to a level," he explains. "The elves start putting it in all the juice and tea for the students as soon as the weather begins to turn." He sighs. "We would have liked to be able to give them low doses of the Harmonia potion, as well," he confesses, "but they don't react well, and we decided that pheromone reduction should take priority. Besides," he adds sourly, "a number of parents take it as a personal affront or a cardinal sin if students are over-friendly with peers of the wrong House or demographic."