aka Operation Mercury

Story, first published: Astounding Science Fiction, March 1941

Earthlings, using Mercury as a base to beam solar power back to the rest of the Solar System, give little thought to the natives, the Candles who can mimic any life form, even humans. In their lust for energy, Earthmen turn them into clowns, "a troupe of mimics, absorbing alien ideas, alien ways" (p. 73). One of the Earthmen, in foiling a plot by the Mercurians to take over the power station, realizes that the Candles are not curiosities, but a victimized race of intelligent beings.

Ewald, Robert J.: When the Fires Burn High and the Wind is from the North, p.28-29