During Sam Winchester's soulless period, he and Samuel Campbell were hunting an arachne that was taking men in their thirties, and poisoning them in order to turn them into arachne to presumably feed on. They tracked the arachne down to Bristol, Rhode Island, where they enlisted the aid of Roy Dobbs. Sam, being soulless, used Roy as live bait and let the arachne capture him so that he and Samuel could track the monster to her lair. There, Sam killed the female arachne by decapitating her. Roy, being eaten alive, is told by Samuel that he'll be taken to a hospital but is stopped by Sam, who says they're dead men walking. He suggests killing them and burning the bodies as to remove the evidence. Sam calls Roy a hero and mentions that he saved a lot of lives, and Roy, begging for his life, is shot along with the other arachne victims. Sam and Samuel burn the building with the victims inside. Unbeknownst to them, the infected men, including Roy, survived and managed to escape.
A year later, Sheriff Roy Dobbs, now an arachne, lures Sam back by sending him coordinates via cell phone and taking women that Sam slept with in order to exact revenge. Sam, who has regained his soul, initially remembers nothing of the original hunt, but it returns to him in flashes of memory. Dobbs catches Sam and Dean and has come to believe that Sam and his wife, Brenna, have been sleeping together and the whole reason he got rid of him was to get to her. Roy goes on to explain that arachne wasn't feeding, but breeding, and that he and the other victims escaped with their lives. He then went on to brag about how he turned women Sam slept with before allowing them to disperse. However, Roy admits that he was confused as to why Sam didn't figure any of this out earlier until he learned that the younger Winchester had no memory of the events of the original hunt. Due to this, he ponders on whether or not he should kill him as originally planned or simply turn him for revenge. Roy overpowers Dean when he escapes to attack him, but Brenna sets Sam free, enabling the latter to decapitate and kill him. His death deeply affects Brenna and Sam admits to feeling guilty about what he did.