Shiva was in meditation in his home on Mount Kailasa. Crossed legs, straight back, the mind quieted, he was entirely focused on the Atman, the Self, the Supreme Reality, his eyes half closed allowed the world to exist. All was peace and harmony.
Parvati, Shiva's wife, saw her husband in this state of absolute bliss and approached him from behind, silently, stealthily. Once close to Shiva who had not noticed her, both her hands covered his both eyes.
It was just a joke, an innocent game, but in the way the light was removed from the world. Deepest darkness covered the entire universe, a deathly silence enveloped the globe. The trees whitered, the fields are drained, the rivers and oceans dried up, the winds stopped blowing, living things began to die. The disorder and the death raged unabated.
Then Shiva, in his infinite goodness and mercy and through his divine powers just by force of will he grow an eye in the middle of the forehead and, with that eye open, gave back the light and life to the universe.
Without the eye that is turned inward in search of self, without the eye that sees beyond the material things nothing can exist.