The Sarrians are an intelligent species native to the hellish world of Sarr; a small planet in close orbit of a huge blue star. As a result, their biology is based on an alternative biochemistry that only works under extremely hot temperatures (by our standards). They breathe gaseous sulfur and drink copper sulfate, both of which are naturally cycled by the planet's biosphere, similarly to how oxygen is cycled on Earth.
Although a spacefaring species, they are not fully familiar with the vast possibilities for alien life; and are particularly surprised to find life based on water. They refer to Earth as an uninhabitable "iceworld", though the word is a translation liberty since "ice" is obviously not part of their daily experience; "solid sulfur world" is a more literal translation of how they think of the planet.
Physically, Sarrians are quasi-humanoid, but possess three-jointed legs and two pairs of tentacles instead of arms. They are slightly shorter than the average Human, have flat nose-less faces and two eyes that move independently from each other. They appear to be a rather peaceful people with strong scientific curiosity; although criminal activity is known to exist on their society as much as in any other.
Curiously, despite having an extremely different metabolism, they are also susceptible to the addictive effects of the Earth plant tobacco - which obviously becomes a gas in their environments.
- Iceworld, by Hal Clement (1953)