The A9000 Robots were robots owned by Mr. Burns made to be employees at the Springfield Nuclear Power Plant. Each robot is assigned a specific alphanumerical identity. They could only do what they were assigned and would not stray from this. The robots that needed to move would only follow the yellow guidance trails through the power plant. After accidentally breaking a robot, Homer read the A9000 Repair and Maintenance Manual and found out he could make them interact with him.