"Joker had become obsessed with obtaining immortality," because of me, he leaves out, trying to keep this contained on one horrible trajectory at a time, "and in a last-ditch grab for it after experimenting on himself to the point of a significantly quicker death anyway, started shooting up a super-steroid called Titan, a failed attempt to re-created Bane's Venom. It reacted with whatever was already in his blood, and created something unthinkable. Not unlike a prion infection. Transformative and fatal."

Bruce keeps his voice clinical. He doesn't look at Clark. The transformative nature of Creutzfeldt-Jakob and other prion diseases is not so much that; it only looks that way, as the brain begins to melt away cell by cell. The behaviors that develop as the disease progresses are nightmarish, and coupled with the most common form of transmission - consumption of human spinal fluid - gave rise to the mythos of zombies.