Gadmeer

The Gadmeer are a races of aliens from the Stargate Universe. They are reptilian/amphibian in appearance, but unlike most life in the Milky Way galaxy, they are sulphur-based organisms. They are a technologically advanced race. The Gadmeer were wiped out by a larger military power and are currently extinct.

Technology
The Gadmeer had some fairly advanced technology, they had music, sub-light propulsion, some weapons but limited, spaceships, advanced holographic technology, transporters/shuttles, fairly advanced biological technology (successfully grew an adult human), and sensors. Perhaps their most impressive technology was the terraforming technology, able to turn a completely carbon-based ecosystem into a sulphur-based one in just a matter of weeks. This is achieved via an energy curtain that is deployed from a ship.

Biology
The Gadmeer were a sulphur-based, peaceful people. They look reptilian/amphibian in appearance and have two arms and two legs with a tail, their ears are very different from a human's as when humans hear their music, it is unpleasant. This is known to be due to human ears as the human created by the Gadmeer spaceship for communication states "the music sounds most unpleasant, this is down to our ears being of the wrong design".