Beetle Juice by Piers Anthony

Wetzel read her mind, and there it was.
The rape repellant
.
    He realized that this would indeed be a better defense than mere hiding. The mind monster’s attack was similar to a rape, and should be similarly balked. “Do it!” he said.
    Veee focused. The awful repulsion surged. She had improved on it since he taught her. Copulation was disgusting, humiliating, and dirty. She was totally without sexual appeal.
    But still walking toward the monster.
    â€œChange it,” he said. “The monster doesn’t want sex, it wants flesh to eat. Make yourself repulsive as food.”
    She nodded. Her mental imagery shifted from an ugly genital region to a diseased body. She became a virtual zombie, walking decaying flesh, complete with maggots wriggling in holes in her skin. It was sickening. Wetzel almost smelled the stench.
    Something changed.
    â€œI’m free!” she exclaimed.
    â€œCarry Wizard away,” Wetzel told her. “When he is beyond range, return to carry another.”
    She hesitated. “I don’t want to leave the rest of you in danger.”
    â€œDo it!” Tod snapped.
    Veee hastily obeyed. She might be her own woman, but she was highly responsive to Tod.
    Wetzel addressed the bat. “You were there when she learned rape repulsion. You know how it works. Do it.”
    The bat became the woman. “Do it yourself,” she said, and started concentrating. The image of vomit suffused her mind.
    She was right. Wetzel had been so busy addressing others he had neglected to see to himself. He had never been concerned about getting raped, knowing that even if someone wanted to do it to him, he could become the unicorn and destroy the rapist. Now he marshaled his feelings in earnest. He borrowed from Veee’s imagery, making himself another zombie, and added open sores that leaked corrosive ichor.
    And he was free. Just like that, they had found the way to stop the predator. It was repelled by bad meat. It seemed to be an automatic response.
    â€œYou can do it too,” he told Tod. “Picture yourself as dirty, ugly, diseased, and foul-tasting. Maybe even poisonous. Something no self-respecting predator would eat.”
    Tod worked on it. It seemed he had once discovered a rotting carcass, and the odor had been appalling. He pictured himself as that noisome mass, complete with protruding bones.
    It worked for him too. The three of them strode back up the slope, away from the predator.
    They rejoined Veee and Wizard some distance back on the trail. “It seems we have had our first test as a reconstituted team,” Wizard said. “One thing bothers me: why was I so incompetent? I should have devised magic to repel, confuse, or destroy the monster. Instead I was helpless.”
    â€œI can tell you why,” Veee said. “The Amoeba is breaking in our new member. It put us on a route that passes a mental threat, rather than a magical one, so you could not handle it but Wetzel could, once he figured out how.”
    â€œYou were the one who figured it out,” Wetzel said. “You remembered the rape repellant. That was the key.”
    â€œWhich you taught me,” Veee said. “Then you figured out how to adapt it for this purpose.”
    Wetzel smiled. “You seem determined to give me credit I don’t deserve.”
    â€œShe does that,” Wizard said. “She derives the rules of the game, then encourages others to play it. She doesn’t seek credit herself. It is one of her endearing qualities. But she is right: it was your insight and technique that foiled the monster. Had we encountered it without you, we could have been lost.”
    â€œHad we been with someone else, the Amoeba would have led us past a different trap,” Tod said.
    â€œNext question,” Vanja said. “What do we do about that monster? We can’t let it go on eating innocent travelers.”
    â€œNow that we have nullified its power,”