I’ve decided to write an alternate turn of events where Slughorn had more of a sense of humor and Tom Riddle was a bit more naive. When approached about horcruxes for immortality, Slughorn, as a joke, tells him that vampires are immortal and that anything can be found in the forbidden forest. Tom Riddle is caught after-hours, gets detention, bitten as planned, and becomes an immortal vampire… until he’s reminded that a vampires weakness is a piece of wood through the heart which is something all wizards carry at all time.