
These are Elconic rocks, like most things other than snow in Elcon, they come in a number of colours, sometimes even if they're the same kind.

Yellow Coneman: “Hold on, are these rocks or rocks?”
A valid question, in Elcon there's even more possibilities than being rocks instead of rocks.

Red Rock: “Huhahaha”
Handily some rocks will have facial hair like moss, or crags in vaguely facelike formations.

The biggest tell of course is they move around. They may not be natural villains, but they do have hearts of stone and tend to be naughty.
All Rocks: "Huhahaha!"
Yellow Coneman: “HELP!”