^ I think he used a phaser, along with a squad of deputies, to save Kira and Rom in Sacrifice of Angels.
They wouldn' turn the T-1000 into a drone, but adapt the technology and use it to make a totally new brand of morphing drones.
my vote goes to the demon-planet matter. it truly became the person or thing of the shape it assumed, including the mind, personality, memories. the prior existence was wiped out. the founders babbled a lot about becoming something, but never achieved that.