What happens if The Thing is able to absorb all of the biomass on an entire planet? Would it then just be a world of nothing but Thing imitations living out fake lives? Would Thing break up into millions of different Things and attack each other in a never ending cycle? Or would the planet-wide organism go into a kind of dormancy until another species comes along from elsewhere?

Obviously if the Thing took over the entire planet of a technologically advanced species with space travel capability then there would be no problem because the Thing could get off the planet and go to the next one. But what if the planet it takes over has only animals and plants of some type but lacks intelligent life? Is the Thing just stuck there?