They convert all the people they can find.

The Kiwi's and Parella fell easily, so much so that Groose only had to watch as her queen converted the entire population of the forest into slime girls. The rest of the surface came in due time, and with it the Dragons, the old women, the Imprisoned. All life on the surface world was either assimilated into her mass or converted into one of her subjects. The people up in the world of Skyloft had no idea, of course, as they were so far removed from the threat. But years later, when an enormous green slime woman stretched from the clouds to look down at them all, her face regally composed with a hint of a smile, the last solid life fell. Let the slime queen reign supreme.

THE END

...or is it?