This attack makes R.O.B. spin around rapidly with outstretched arms. The attack also lifts R.O.B. into the air slightly, allowing it to be used to aid R.O.B.'s recovery a bit (though this is rarely necessary). It deals minor damage (normally 4%), hits multiple times and has decent stun and knockback. This attack can also reflect any incoming projectiles that hit the outstretched arms. The move can be bit difficult to use as a reflector, as there is bit of delay before R.O.B. starts to spin his arms, thus requiring more accurate timing than the other faster reflectors. Finally, it can be extended by rapidly tapping the special move button. If R.O.B. moves left or right while performing this move, his torso will also bend, if the players presses B multiple times, the attack will have longer duration.
In Super Smash Bros. 4, the move ends with an uppercut that deals increased damage and knockback. The spins also trap enemies more reliably, allowing the entire move to combo well into the final hit. However, the move was still slow and highly punishable, with its KO power being limited.
The move was dramatically improved in Super Smash Bros. Ultimate, where the move now starts more quickly, and is active for less time overall, making the move slightly harder to punish. The move’s window of frames which reflect projectiles was extended, and the KO potential of the finishing blow was increased significantly, making Arm Rotor a devastating KO move when used off stage, especially when directly following up a thrown Gyro or forward aerial.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
The move is an original creation, however the spinning animation is similar to R.O.B.'s victory pose in Mario Kart DS. The R.O.B peripheral in real life could also rotate its arms, albeit at a much slower pace than Arm Rotor.