The human-shaped puppets of the Jet-Black Sect needed energy to move around. The stronger the puppet was, the bigger the amount of energy it required to activate.
After absorbing the spirit stone of the Fourth Stage, the eyes of the puppet faintly lit up. However, they immediately dimmed, and the puppet didn't move in the slightest afterward.
A spirit stone of the Fourth Stage had enough energy inside to allow the silver dragon puppet to fly for a month without breaks. But the same stone wasn't even enough to activate the puppet...
In other words, the human puppet was extremely powerful.
It had to absorb more spirit stones if it wanted to activate, and there just happened to be another eleven spirit stones of the Fourth Stage inside Song Shuhang's size-reducing purse.
The human puppet was unable to move, but the eleven spirit stones of the Fourth Stage would often bump into it while Song Shuhang was battling against the hundred giants.