Read the book: «The Natives»

The old one said, "Stick close by me, child."

"What'll it be like, Grandpa?" The youngster was frightened.

"Dark, very dark, and big. It moves fast, but we'll keep up with it." The tone was consciously reassuring.

"Dark, Grandpa?"

"Yes, it sucks heat and absorbs light. You'll find out when you're old and strong enough to swim down to the bottom and see what's there. Now stay with me when we follow it, and don't get lost in the crowd; and don't get ahead of me or get too close to it – you might take in too much, and get overcharged."

"What's 'overcharged,' Grandpa? Can you really get too much?" The youngster jigged up and down a little with excitement and anticipation.

For a moment, the oldster turned his attention from watching for the thing that was coming, and considered him fondly. "Poor youngling. I forget. You've had no chance to learn what it means to get enough. You're too young to ride the storms and tap the lightnings… Listen now. When a grownup has to let out a flash of blue light, that means that he's overcharged and spinning off balance inside, and so he has to save himself by letting out his energy to let down the pressure. So be careful; take enough, but don't be greedy and take in too much too suddenly. Now let's just float here with the others and be ready."