Compartment C is a carriage of the Hogwarts Express where the 1996 Slug Club had its first meeting. This meeting included Harry Potter, Neville Longbottom, Ginny Weasley, Blaise Zabini, Marcus Belby, and Cormac McLaggen.
It was some ways away from the somewhat far compartment in which Harry and Neville had originally seated themselves. It was roomy enough to accommodate six students and a teacher without any major concerns of anyone being too cramped, though Slughorn's bulk did make things a bit tight.
- Harry Potter and the Half-Blood Prince (First appearance)
- Harry Potter and the Half-Blood Prince (video game) (NDS version only)