Megatron: Prime!
Optimus Prime: One shall stand, one shall fall!
Starscream: Oh, how it pains me to do this!
Megatron: Wait, I still function!
Starscream: Wanna bet?
Quintesson judge: Before the Imperial Magistrate delivers his verdict, would you like to beg for your lives? It sometimes helps - but not often.
Answer: The planet was called Lithone. According to a comic book adaptation, the race that dwelled there were an offshoot of the Transformers who were more emotional. The limited information given on the only two characters named in the movie, Arblus and Kranix, shows that they can transform even though this is never shown.