Organic Rock

 is a huge landmass floating at high altitude at the extreme-East of the world, above the Volcano Mountain.

It is only reachable using Skylands as a startup point, using a  Jetpack and weapons knockback

It is composed of Strange Rock,  Strange Rock Defense and  Strange Rock Heart

The Strange Rock Heart can be completely extracted with explosives, thus achieving the "Xenocide" achievement, but the whole island will start to crumble after this ...