Beast (planet)

Beast (ビースト Bīsuto), or Beest, is a distant planet inhabited by a race of anthropomorphic animals known as the Beastformers. Beast used to be a relatively peaceful planet, with dissenters few and generally quiet about their dissatisfaction with the planet's then-rulers, until the Transformers came to stir things up as they so often do, with each faction joining with their appropriate Beastformer counterparts.
 * English/Malay dub name: Pisto

Headmasters cartoon
While out in space, the Autobots came into contact with two refugee Beastformers who had come to seek help. The Decepticons invaded planet Beest and helped the enemy forces of Alligatoron take control. The Autobots then assisted the good Beastformers, led by White Leo, to free planet Beest from Decepticon tyranny. Rebellion on Planet Beest

Headmasters manga
Once again, the Decepticons teamed up with Alligatoron to take over planet Beest. The good Battle Beasts (now being aided by the wild jungle boy, Kane) sent for help from the Autobots, who arrived to help defeat the Decepticons and Alligatoron. [http://transformers.wikia.com/wiki/Great_Decisive_Battle_of_Planet_Beest! Great Decisive Battle of Planet Beest!]

Laser Beasts manga
The planet Beest was originally a wasteland, scoured by intense heat with no water or breathable atmosphere. When the Three Wise Men crash-landed there, they immediately moved underground and developed the vast subterranean empire of the Laser Beasts. 20014 years later, after hostilities between the Laser Beasts began to develop, a group of peaceful Laser Beasts traveled to the surface of Beest for the first time ever. They found the planet had changed drastically since the Three Wise Men founded their civilization, having become a jungle abundant with life. Meanwhile, a great flood wiped out the subterranean empire, leaving the remaining Laser Beasts to journey to the surface as well.

Encountering the Beastformers for the first time, the two Beast lifeforms immediately clashed in an all-out war which would decide the fate of planet Beest.

Dreamwave comic continuity
After being ejected out into deep space by Starscream, Megatron found himself on the planet Beest in the middle of the war of the Battle Beasts. Megatron became aware that the Predacons had taken refuge on Beest and proceeded to hunt them down. Welcome to the Jungle

Devil's Due comic continuity
It was likely consumed by Unicron, as natives of the planet are seen living within his body as mind-controlled "anti-bodies".