The Unnamed Armored 6-Legged Beast was a predator native to Andalite Homeworld. The creature moved about on six legs as big as tree barks supported by knuckled feet. It head moved back and forth every time it moved. The beast was also protected by a thick hide of natural armor that easily protected it from an Andalite Tailblade. Despite it's large size, the creature could make fast bursts of speed to charge it's prey. They are apparently the Andalites natural predators during tribal times.
When the Ellimist was hiding from the Crayak on the Andalite Homeworld during the Andalites tribal period, he found a village being attacked by one of these creatures. The creature easily killed two Andalites, and even stopped to eat them as the dead Andalite's comrades slashed the creature to no avail. The Ellimist, againest his judgement, pulled out some sort of blaster and shot it in the head, killing the beast. After that, the Ellimist disguised as an Andalite, became a hero to that Andalite tribe.