The Scalosians were once a thriving civilization. They come from the planet Scalos in the Alpha Quadrant.
They had a high regard for art. With this, they had beautifully designed buildings.
They dressed in metallic-looking fabrics. Men favored tunics while the women wore translucent and revealing garments.
A passing comet bombarded Scalos. This resulted numerous volcanic eruptions that poisoned the water. This poison killed off the children and most of the adults. It also left the survivors sterile.
Scalosians were left invisible to the eye and time quickly went by them. A second to them would be an hour to humans. They began to look on ways outside of their population to repopulate.
They sent a distress signal that was picked up the U.S.S. Enterprise. They began to hyperaccelate the Enterprise crew. The crew would die quickly because they would burn out.
They did this to other species too. Doctor Leonard McCoy found a cure for this hyperaccelating. Captain James T. Kirk sent the remaining Scalosians back to the planet. Starfleet then warned others about what the Scalosians were doing and warned them to stay away. It is nearly certain that the Scalosians have all died out.