Chimeron

The Chimeron (pronounced shimmer-on) were a race of Humanoids who were nearly made extinct.

Appearance
Chimerons hatched from large grey eggs and started as green, wrinkly infants. Though males kept this appearance throughout their life, the queens of the species had a slightly different development. In order to properly develop, the young queens were fed Chimeron Jelly until they were fully grown. In the first few hours, they rapidly grew and became more Human-like, developing hair and other more distinct facial features starting to lose their wrinkles. Adult queen Chimerons looked similar to Human females with slightly green skin and grey patches behind the ears. (DW: Delta and the Bannermen)

Abilities
Chimeron queens also developed a strong singing voice at this age, partly as communication and partly as a powerful means of defence. Once they reached the Singing Time, they perfected their defensive songs and reached closer to adult size. Adult queens could detect high frequencies with grey patches behind their ears. (DW: Delta and the Bannermen)

Technology
They were equipped with high level weaponry. It is unclear if they possessed space craft of their own but Delta's ability to pilot one suggests it is so. (DW: Delta and the Bannermen)

History
The Chimerons were nearly wiped out by the Bannermen, but the last queen, Delta, was able to escape with an egg. The egg hatched on Earth, and with the assistance of the Doctor, Delta and her daughter were able to escape annihilation by the Bannermen. They left Earth along with Billy, a Human who Delta had fallen in love with. He took some Chimeron Jelly so as to become a Chimeron; without him the species could not continue. (DW: Delta and the Bannermen)