The Qetesh is a species that developed an advanced civilisation capable of star travel. They feed off powerfukl emotions such as excitement in people's lives, draining their life essence with it and are therefore masters of emotional manipulation ot achieve sustainance. They are also known as "soul-stealers".
Their stomachs existed outside their bodies, and they did not need air to breathe. The mobile part of their body has been known to look human, but they are most proabably albe to make it match the appearance of their prey's nature to better manipulate them into generating emotionnal food.