Ranked, as difficult as that is as all of these things are so close together:
  1. Being burned
    If this were to occur, I pray that there is no recovery. There is no pain like recovering from being burnt
  2. Drowning
    Being strapped in and can't get free underwater, cold sweats just thinking about it.
  3. Snakes
    Doesn't matter. Start shooting. Let God sort it out. This include rubber and stuffed ones!
  4. Clowns
    What sort of evil beast travels about unable to stop that incessant grinning?
  5. Dolls - specifically China dolls
    They stare at you no matter wear you are in the room. They follow you around the room looking for a weak moment when they can attack!