The Diffusion Beam is R.O.B.'s Final Smash. R.O.B. shoots short-ranged whirling lasers out of his eyes (with almost no knockback), followed by some hard-hitting short lasers (with tremendous knockback). Similar to the Superspicy Curry. R.O.B. can move freely during the Final Smash. Being in the general area in front of R.O.B. causes damage that rises at a 2% damage rate and as long as R.O.B. is in front of an enemy, he will continue doing damage. The short-ranged laser has decent knockback. But as the move has such a short range, it is one of the most easily avoided Final Smashes. However, it lasts for a decent time and renders R.O.B. invincible for the duration, resulting in somewhat of a chaos as he chases opponents around the stage, trying to catch them in the deadly vortex of his eye beams. He can also use his entire moveset (minus a few special moves) during the Final Smash and can even use items.
R.O.B.'s Final Smash. He emits a beam from his eyes that spreads across the spectrum and undulates in great variety as it travels. What makes this technique different is R.O.B.'s ability to move while using it. This allows him to use it in combination with his other moves to increase his Final Smash's effectiveness.
For some strange reason, this Final Smash is the only one that was not described on the DOJO.
R.O.B. is the only character besides Jigglypuff who can benefit from the Bridge of Eldin Final Smash glitch, giving him a never ending Diffusion Beam (Jigglypuff's makes it remain huge). Although, in order to make this happen, the player must have R.O.B. get caught in the re-materialization of the Bridge during the close-up animation that starts the beam. If the player does it at any other time, R.O.B. will merely take damage, and waste the time of the Final Smash. Strangely, if you use it right as the bridge becomes solid, R.O.B. will be invincible and will make the noise of the Diffusion Beam, although he is not using it. However, using his Down B will make part of the beam reappear, which will be harmless. Using the gyro again will bring the beam back. If R.O.B. enters the negative zone with infinite Diffusion Beam he will take damage and suffer the Negative Zone's effects. If the Zone ends with R.O.B. sleeping, he will remain sleeping until the Negative Zone is used again on him and the effect is replaced.
Even though R.O.B. can grab and use items during this state, he cannot use items that activate on contact (i.e. Starman).
Because the lasers are emitted from R.O.B.'s eyes, they point in whichever direction his head is facing. This makes it possible to hit crouching enemies by also crouching, or hitting enemies above by using his side taunt (which makes him look upwards).