As the glow grew brighter, the ordinary looking rock began to change. Its irregular surface shifted into a smooth-sided cube. Once that was finished, all color faded away until the cube was as transparent as glass. Then, it slowly began to expand, leaving a hollow space in the middle. It was like watching someone blow a square sided bubble.
John was so fascinated by the changing object in his hands that he didn't notice the fact that the former rock was no longer the only thing glowing. Both of his hands were glowing too, and it was spreading. The further the cube expanded, the further the glow traveled up his arms. The cube had started out measuring only a couple of inches on a side. In the time it took to slightly more than double those dimensions, the glow was up to John's elbows.
Dark, moist soil welled up from nowhere, filling the lower portion of the hollow space within the cube. Green shoots thrust their way out of the soil, stretching and unfurling leaves far faster than any normal plant should. In minutes, the once empty space looked like a miniature jungle. The cube continued to expand. Soon, it was almost too big to fit in the sink.
John felt a faint tingling in his back and shoulders, but he thought it was simply the result of standing bent over in one position for too long. He was still completely focused on the transformation taking place in his sink. He didn't realize that the unnatural energy from the still-growing cube had already engulfed his arms and was rapidly traveling across his torso from both sides at once. When the two advancing waves met in the middle of John's body, there was a blindingly bright flash of light and a sudden explosion of force that blasted him away from the sink.
It didn't kill him, but later, whenever he remembered the incident, John would always wish that it had.