hm, i have my doubts that deadman could possess him for any significant length of time before thanos drove him out. thanos is definitely insane, imo, and DM couldn't handle the joker. barring that, thanos' willpower is among the tops in marvel. i'm also pretty sure that deadman is NOT immune to telepathic attacks. don't really see anyway for deadman to win this. probably spite unless someone knows something about DM that i don't....