Predator flash weakness

A half dozen bewildered guerrillas turned and looked back up the hill, searching for something to explain the freak disaster. As they stood there stunned Schaefer was a beat ahead of them. He pulled the pin of a pinecone grenade and footballed it into the air. It arced dead center for the camp, spiraling above the guerrillas’ heads, then bounced on the ground twice before it rolled into the fuel dump. There was a moment’s agonizing pause, during which even the jungle twitterers seemed to hold their breath. Then the grenade blew, igniting the fuel, and the dump exploded in an incredible fireball, roaring yellow and orange with thunderous crashes. Shrapnel whizzed in all directions, razoring a guerrilla’s arm at the elbow, blinding another in one eye.

The banana palm on the downhill slope suddenly seemed to shrivel. The alien withdrew to the safety of the ground as if it couldn’t bear the intensity of what was starting to happen. Its optic cells were blinded by the white-hot flashes of the explosion, its heat-sensitive radar temporarily overwhelmed. Power like this made it frightened of men, and it hated to be frightened. It had its own code, if nothing so real as pride or honor. It simply could not tolerate any power more explosive than its own, so it sank into itself to figure out a strategy. It had to win, even here on this weakling planet whose creatures were bent on destroying one another.

   The Predator (1987 novelization), chapter 5