Severus Snape emerged from the Whomping Willow into moonlit chaos.

A grubby man grappled with a struggling armful of bestial fury, which flung him to the ground before three terrified children.

Staring backwards over his shoulder as he fled in panic, a second man slammed blindly into Snape. This coward squeaked upon identifying his obstruction, and the full moon revealed pointed features long familiar to the Head of Slytherin.

"Pettigrew!"

Recoiling from the Potions Master's grasping hand, Pettigrew shrank into his Animagus form and scurried past the cringing children toward the rising moon.

"Wormtail's escaping!" shouted Harry Potter, pointing in despair.

As Snape strode forward, the grubby man transformed into a large black dog, but it was too late to stop the werewolf, who spotted the fleeing rat and snarfed it in a single gulp.

The man in black, the trio of Gryffindors, and the Grim-like canine stared at the drooling werewolf in horror.

"Pr-Professor … did I just see…" whispered Harry, aghast.

Snape replied gratingly, "It appears that Professor Lupin missed his meds tonight."

"But I meant – "

Thrusting his nose moonward, the werewolf howled, a burst of steam escaping his snout when the eerie wail culminated in a pronounced burp.

Improbably, the dungeon bat and the Boy-Who-Lived shared an involuntary, moonlit chuckle.