Gengar channeled together his own latent dark energy and created a ball of shadows, which moved slowly toward the chest of the currently unconscious gardevoir, but as the ball made first contact with her, something unexpected happened.
The ball of shadows became a ball of light, and stretched into a beam of great light that could be seen for miles, someone on a ship in the south pole 100 years earlier who could control the element of fire even saw the beam of light and mistook it for a sign of the awakening of a human who could control all elements.
Gengar understood what had happened, the ball of shadows did not contain enough dark energy to corrupt Gardevoir's pure energy, rather the opposite happened, her own pure energy had penetrated the shadow ball and turned it to light! Gengar realied that the corruption of the pure Gardevoir would be a much harder task than he had anticipated, but one good thing had happened, some of Gardevoir's pure energy had been drained, but the shadow ball took some of Gengar's energy as well. Gengar knew now, that if he wanted to corrupt Gardevoir, it would be a gamble!
To corrupt Gardevoir would be a gamble, a gamble of who had more power. If Gengar had more dark energy than Gardevoir had pure energy, than once Gardevoir had run out of pure energy to cancel out his dark energy, she would be corrupted, but if the opposite was true, then Gengar would run out of energy to drain Gardevoir's pure energy, reducing him to a mere husk of an energyless body, and Gengar was taking the gamble!