Bug (The Golden Bugs)

These bugs are an unnamed species of sapient extraterrestrial creatures which came to Earth in the mid-20th century with the intention of gathering metals. Their ultimate goal remains unknown, as they didn't communicate with Humans, and seemed in fact to entirely ignore humanity.

Biology
At first glance, these creatures resemble gold-colored, slightly-oversized ladybugs. Upon close examination, however, they reveal themselves as being completely different creatures. Unlike Earth insects, they lack any kind of body segmentation or antennae, and their carapace is incredibly thick and resilient. These traits, combined with their ability to retread their head and legs into their carapace, make them seem more akin to miniature turtles than to actual insects.

The bugs are mineral-based creatures, whose internal structure resembles fine quartz-like crystals. They're known to collect metal, but seem to feed exclusively upon agate. Due to their mineral structure, they cannot be properly dissected, and need to be shattered with a hammer for one to be able to see their insides. Their most notable ability is that of telekinesis, which allows them to effortlessly move objects several hundred times larger than themselves. According to Dr. Darby Wells' observations, they most likely operate under a hive mind.

Being crystalline life forms, the bugs' bodies are vulnerable to certain sound frequencies which cause them to crumble to dust.

Culture and society
Nothing is known about the bug's origins and motivations, although it seems that their telekinesis has spared them of the need to develop actual technology. Their spaceships, for instance, are nothing more than agate-made hollow boulders, almost two meters in diameter, propelled through space by their occupants' mind powers.

The bugs that came to Earth landed on Randall Marsden's property and, at first, were deemed useful as they killed all the ants and wasps and cleaned Marsden's house neatly. However, they soon became a nuisance and later a threat as they started using their telekinetic abilities to destroy the furniture in search of screws, nails and any kind of metal they could locate. They were eventually destroyed by a sound-generating machine created by Marsden's neighbor, Arthur Belsen.

Appearances

 * "The Golden Bugs", by Clifford D. Simak (1960)