This shader follows the concept of classic height shaders commonly seen in games to create texture blending between snow and ground textures or similar.

Applying this shader structure onto Blender metaballs is following Corza's concept.

The shader works through procedural noise textures to create the rock displacement and general rock textures that blend by height.

The effect really comes through due to Blender's metaball meshes. They connect by distance to create a seamless mesh effect.