Bouncer

Bouncers are an unusual life-form native to the world of Chbal. They are spherical, 1-2 metres in diameter, red with yellow veins, and have no organs or limbs apart from their normally invisible, claw-like feet.

A bouncer's body is light, as its skeleton is actually formed from inflated sections of its own tissue. In the windy atmosphere of Chbal, Bouncers travel vast distances, following the wind patterns, floating across oceans and bouncing their way from continent to continent. Their bounces can be several metres long and sufficiently high to reach a second story window, and in appropriate wind conditions this bounce can be extended considerably. They are known to live in caves.

Bouncers are lively and inquisitive creatures with playful natures and alert minds. They have an intelligence somewhat lower than that of any truly sentient species, but can mimic speech and take great interest in the activities of other creatures. Bouncers are not hostile unless provoked, when they will attack by bouncing onto their victim and delivering an attack with their long, taloned claws. These creatures are quite fragile and any rupture in their skin will usually deflate and kill them.

Source Warhammer 40,000: Rogue Trader (1st Edition), pg. 207