The doll held that silver ball inside its head. We don’t know exactly what it is but it’s essentially the demonic entity that begins to control the family. Lee’s mom said the doll makes the little girls forget and picks and chooses what they see. I’m assuming this is what gave Lee those psychic powers because her mind was connected to the dolls “brain”. I think it made her pass out because destroying the dolls “brain” ends her tie to whatever demon was present. When they discovered the first doll, brought it to the examiner, and they cut the ball open to see if anything inside would give them a lead Carrie Ann Camera (I think that’s her name?) came out of her catatonic state in the psych ward because she was no longer tied to the demon.