The Great Rock Serpent’s body is composed of several massive gray boulders, its sinuous form resembling that of a giant serpent. A long, rocky horn protrudes from the top of its head, while two dark eyes gaze downward; from the midsection to the tail, the boulders gradually decrease in size.

Normally, the Great Rock Serpent dwells underground, where it writhes its long, sturdy body to burrow forward while ingesting various hard objects, thereby strengthening its physique. When digging underground, it can reach speeds of up to 80 kilometers per hour, causing the earth to tremble incessantly and producing a thunderous rumble that carries far and wide. As it grows older, the stone portions of its body become as hard as diamonds—only they are black. Thanks to magnetic particles in its brain, it never loses its way even when tunneling through the ground. The older it gets, the more rounded its body becomes. After it passes through, the resulting tunnels are often taken over by moles as their homes; occasionally, Red-Faced Dragons will also dart through these narrow passages, hunting and capturing prey.