I have now killed two naked iPhones in the same manner.
-- Put iPhone down on granite countertop.
-- Do not notice small amount of moisture on said countertop.
-- Go to pick up iPhone, which is now invisibly adhering to the smooth surface due to said moisture.
-- iPhone does not, as anticipated, detach and rise into the air. Rather, it squirts horizontally along the counter as apparently frictionlessly as an air hockey puck, eventually runs out of counter, briefly attains independent flight, meets tiled kitchen floor and that's all she wrote.
Always wear a rubber!