The bottom of this space was a little special. The stones here were all greenish-black in color, which looked very strange. Zhao Hai stomped his feet hard, but there was a clatter, as if he had knocked on iron.
Zhao Hai was stunned. He had used a lot of strength just now. Even real iron would have a few holes in it. But why was there only sound now? there was not even a single mark.
Zhao Hai squatted down and studied the floor of the space carefully. The floor was very strange. It didn't look like it was made of iron. It looked like an ordinary stone, but what kind of stone could be so hard?
Zhao Hai knocked on the ground two more times, but there was still no reaction. Zhao Hai was even more curious. His hand turned into a claw and scratched the ground. There was a clang, but the ground was still the ground. There was still no mark.
