The attack encompasses a spin top that R.O.B. fires. It is chargeable; the longer it charges, the stronger and faster it becomes. A fully charged Gyro normally inflicts 18% damage and has high knockback in Brawl. After being launched, it can be picked back up and thrown at the opponent, inflicting 10% damage. An opponent can pick it up as well. It also acts like the Unira in that it will still cause damage on contact as long as it is spinning. Its knockback direction is decided by the direction the thrower was facing, even if it was thrown up or down; this makes it an effective tool for trapping opponents into unavoidable combos.
Each R.O.B. can only have one originating gyro on the screen at any time and can use Gyro again as soon as the previous gyro leaves the screen. If the move is attempted when R.O.B. cannot reuse his gyro, he goes into his Gyro-charging stance and makes a motion with his arms as if to spin a gyro, but no gyro appears. As the Gyro is treated like an item, it can be glide tossed; which, combined with R.O.B.'s very fast and long glide toss, makes this move an asset in his approach.
Much like Donkey Kong's Giant Punch and Samus's Charge Shot, it is an auto-charge special. Gyro does not attack instantly when used. Instead, its initial use begins a charging process. The input must be performed a second time to fire the gyro (as well as tapping any attack button during the charging period), while shielding or moving left or right into a roll during said period of charging can cancel and save it for later to charge for another time. And at full charge, the charge will automatically cancel. Cancelling it in the air will also make R.O.B. drop his charge and cancel it normally. Getting hit or dying while charging however, will cause R.O.B. to drop the level of charge and he must charge the move like normal again.
Unlike most other chargeable special moves, Gyro can actually be interrupted with instant charge-canceling. This effectively gives R.O.B. near-instant access to his neutral attack, tilt attacks, and smash attacks while charging his Gyro.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
The "Gyro" is essentially a spinning top. The R.O.B. accessory for the Nintendo Entertainment System would spin the gyros on a spinner and use them to press buttons to activate in-game effects for the game Gyromite; the button would remain pressed only as long as the gyro retained enough speed to remain upright. The concept of the move in Brawl is exactly the same as when the gyros were spinning in the Spinner, but throwing the gyro is a new feature added in Brawl.
The "Gyro" in Brawl is designed exactly like the real Gyros, but the spinner seems to be based on the "Gyro holder", where the Gyros had to be placed for R.O.B. to pick them up, rather than the actual spinner. Another difference is that to play Gyromite, R.O.B. has specific hands designed to pick the Gyros, while in Brawl he picks them with his regular hands, based on his Stack-Up hands.