Bladderhorn

Bladderhorns are a species of alien analogous to terrestrial antelopes which appear in the Discovery Channel TV special Alien Planet.

Description
Herbivorous creatures, Bladderhorns inhabit the mountainous areas and high plains of Darwin IV where they feed upon the roots and bulbs found across these sparse regions. Aggressive in nature, they are bipedal animals which sport a pair of unusual horns which are employed during territorial disputes, against potential predators, and as a mating display. These horns each contain a bioluminescent bladder (hence their name) which they are capable of inflating with the methane gas which their bodies naturally produce to make themselves appear larger and more formidable. In both contests over territory and mating duels, Bladderhorns are known to engage in a ritualistic butting of heads to determine which gains the appropriate rights, and have been known to charge other animals which they believe to be a threat.