All were monsters

"All were monsters by Manly Wade Wellman" is a science fiction short story written in the mid-20th century. The tale centers on first contact between a human and an alien scout, using that encounter to explore humanity’s fragility and an outsider’s shock at Earth’s abundant animal life.

A solitary farmer is visited by Provvorr, a telepathic visitor who arrives in a ship tailored to match human expectations. Provvorr demonstrates advanced abilities—transmuting a fork to gold, reviving a crushed moth—and explains he is scouting a future colony, assuming humans will soon destroy themselves. But when he encounters the farmer’s dog, Skip, and cat, Oscar, he panics: on his world there are no other animals, and Earth’s creatures are unreadable, uncontrollable “monsters” to him. Repelled by this teeming biodiversity, he abandons the colonization plan. Before departing, he shares a strikingly simple way to avert humanity’s self-destruction—left tantalizingly undisclosed—so the farmer can pass it to the United Nations. (This is an automatically generated summary.)