The Joker

The Joker has apparently died several times, but he is still around, and hasn't slowed down much. Bodies have been found at explosion sites and in the middle of flaming wrecks and positively identified, but he keeps coming back. Apparently the chemical bath caused more than just a cosmetic change. Some people theorize that he is essentially a virus that retains the memories and attitudes of its original host and transmits them to the next host.