Rockies are often hidden amongst the stones. They are living creatures half-animal half-mineral, their bodies are made entirely of Lodestone. This gives them the power to produce electricity at will by rubbing their bodies.
To unlock this Dinoz, you need to have a Dinoz (minimum level 13) win a battle against the Strange Stone in BrutForce.
Some Rockys, when reaching level 10 or so, start to enlarge very much.