Armstrong is introduced as Gyro's latest invention. He is helpful for a while, until he takes over Launchpad and Duckworth's jobs. Then he turns bad, steals Scrooge's money and holds him and Gyro hostage. He was defeated when water from Launchpad's plane was dumped on him, causing Him to short-circuit and fall to pieces.
In the first episode "Woo-oo!", Armstrong's head is shown to be kept inside Scrooge's garage. Also, in "The Great Dime Chase!", Armstrong's name can be seen in Gyro's notes, indicating that he was among the robots built by Gyro that ended up going rogue.
- The robots in "Robot Robbers" bear a strong resemblance to Armstrong.
- Armstrong was mentioned in the episode "Robot Robbers" as "The Last Robot".