The rope and the snake
Once upon a time there was a man who was very afraid of snakes. He went for a walk in the forest one night, and his face brushed past a rope that was hanging from a tree. He died of shock.
Who killed the man? Could it be a rope? But a rope is harmless! Could it be a snake? But there was none?
It was the man's fear that killed him. What is the rope in your life?
At a deeper level, this parable, which is called the 'rajja-sarpa' (snake-rope) story in classical Indian philosophy, illustrates the power of mental models and is used to examine the role that mental concepts can play in physical reality. For instance, if one adopts the solipsistic view of the world, that is, you cannot tell whether you are a 'brain in a vat', then how can you explain this story? Similarly, this story illustrates the role of consciousness (would the man have died if he was sleepwalking?)