Reminds me of that riddle where two friends go to lunch and they each order cocktails on the rocks. One downs her drink and orders refills, downing four more over the course of the meal. The other slowly sips her drink and has a total of two during the meal--and she then drops dead at the end of the meal, while the first friend is unaffected. It is revealed that the drinks were poisoned, that all seven drinks were poisoned equally, and that the poison was the cause of death. So why did the friend who drank five drinks live, while the one who drank two died?

Answer: the poison was in the ice.