Chris, while deliberating over Justin's ass and what else to do with it, had made a small mistake: the apple.
Stonewood Dormitories, being for students and faculty with magical talent, also had magical faculty, and more than that, magical items belonging to magical faculty. As such, the apple on the teacher's desk was none other than one of the Golden Apples of the Hesperides, or really, what happened when the Golden Apples of the Hesperides were cross-pollinated with the Apple of Knowledge, producing a beautiful magical golden apple that the teacher had wanted to study, but hadn't quite gotten around to experimenting with.
As Justin sucked its juices, they burned down his throat, marvelous and intoxicating, the nectar of the gods. It caused his cock to stiffen, then pop out of his ass as it continued to grow, forming the head of a serpent at the end as it grew longer and Justin suddenly could see out of the end of his own cock as the eyes opened. "Ssooo," he lisped with his cock's new serpent tongue, "you wantssss to play with sssspellssss," his cock swaying hypnotically before Chris's face as the upper classman stood mesmerized. Justin's corkscrew tail grew longer and longer, forming scales, twining like a vine around Chris as he ate the rest of the apple, his tusks being joined from above by cruel fangs as his mouth elongated into a crocodilian snout and he grew larger and more reptilian.
Finally, his coils lay about the room, as he became a cross between Ladon, guardian dragon of the Hesperides, and the serpent from the garden of eden, with a little bit of the dragon from the Babylonian creation epic as well, plus two heads, one of them being the end of his serpentine cock, and twice as much brain power between them.
What to do with Chris now that the apple had turned Justin into a lindwyrm?