The Captain met this creature in Beta Orionis I, the Umgah homeworld. This talking pet was different from the others, cause the Umgah had somehow restored it's dormant sentience. It was now a fully sentient Dnyarri, which like it's ancestors, could control minds. It controlled the entire Umgah race and even compelled the Captain to travel deep into the hostile Ur-Quan terratory. The Kzer-Za, however, let the captain go as a reward for revealing this new threath.
The captain returned after acquiring the mystical Taalo-Device, which somehow prevented the creatures psychic attacks. after the captain destroyed the Umgah squadron sent to kill him, the creature suddenly changed approach, becoming deviously kind. It offered to help the captain to defeat the Ur-Quan, which the creature hated with every fiber in his body.
Though the creature acted as a friend to the captain, it's quite clear that it was manipulating him to his own, devilish plans. Make no mistake, this creature, like it's ancestors, was pure evil.