The Mechanical Arm is the very first obstacle Mickey faces in Epic Mickey, within Dark Beauty Castle. Resembling a Swiss army knife, the Mad Doctor used it as an attempt to extract Mickey's Heart. The Mechanical Arm has one eye (blue when docile and red when hostile), a large metallic claw hand and wields various sharp utensils, from scissors, a corkscrew, a chainsaw, and finally a plunger under the manipulation of the Mad Doctor. Fortunately, Mickey escaped his bonds and tried to confront the Mad Doctor, who then used a hatch to escape.
Oswald attempted to follow after the Mad Doctor to escape from Mickey, but he broke a lever on the main controls that manipulated the Mechanical Arm and it overloaded. This caused the Mechanical Arm to go haywire, furiously grabbing and clipping for Oswald with its scissors, corkscrew, chainsaw, and metallic claw before he barely managed to escape. The Mechanical Arm then turned its attention back to Mickey and attempted to kill him, but with the help of Gremlin Gus, the machine was shut down when the control panels were destroyed.
When Mickey returns to Dark Beauty Castle to defeat the Blot, the only thing remaining of the Mechanical Arm is its eye. The rest of its body was presumably washed away by the overflowing thinner in the room.
The Mechanical Arm attacks Mickey with its corkscrew if he is in its line of sight. It was noted that the Arm never used its large, metallic claw when fighting Mickey, but only used it when attempting to crush Gremlin Gus.
According to the novelization of Epic Mickey, Mickey thought of the Mechanical Arm as "a jackknife on steroids."
The Mechanical Arm
The Mechanical Arm's Main Controls
The Mechanical Arm before being powered on.
The Mechanical Arm peering down at the camera.
The Mechanical Arm Examining Mickey.
The Mechanical Arm threatening Mickey with its Scissors.
The Mechanical Arm pulling out its Corkscrew.
The Mechanical Arm Pulling out its Chainsaw.
The Mechanical Arm pulling out its Plunger.
The Mechanical Arm about to use its Plunger on Mickey.
Oswald unintentionally breaking the Mechanical Arm's Controls.
The Mechanical Arm's eye turned red
The Mechanical Arm Enraged
The Mechanical Arm In-game
A view of The Mechanical Arm's Body
The Mechanical Arm looking for Mickey
The Mechanical Arm about to attack
The Mechanical Arm attacking
Sideview of the Mechanical Arm
The Mechanical Arm attempting to stop Mickey from breaking its Control Panel.
The Mechanical Arm successfully attacking Mickey.
The Mechanical Arm after one Control Panel is destroyed.
The Mechanical Arm after having both Control Panels destroyed.
The Mechanical Arm Destroyed.
A close up of the destroyed Mechanical Arm
Bird's Eye view of the destroyed Mechanical Arm
Back view of raw destroyed Mechanical Arm
A Control Panel
A damaged Control Panel
A destroyed Control Panel
The Hidden Room unlocked by the Mechanical Arm's destruction.