The second item was a seemingly ordinary black rock.
Perfection Stone – 100 billion.
This rock's ability was very simple. It scanned a person and morphed into a clone. However, this clone would detect your weaknesses and fix them. The issue was that the rock wouldn't be able to communicate exactly what these issues were.
According to the description, it was a rock forged in a very famous Dream Force dense region. It was able to project the consciousness of the universe by simulating what it could have done with a talent of your caliber if you appeared in a Zone.
It would simulate your life based on your age and then form a clone that could be considered the perfected version of yourself.
The only way to slowly tease apart the details was to fight this rock again and again, not to mention getting beat up again and again. How could you defeat the perfect version of yourself?