The Diffusion Beam is R.O.B.'s Final Smash in Super Smash Bros. Brawl. R.O.B. fires a continuous stream of short-ranged whirling lasers out of his eyes (with almost no knockback), followed by some hard-hitting short lasers (with tremendous knockback), enough to KO at high percentage.


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 can be avoided by small and fast characters like Sonic. 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 (except his neutral special move) during the Final Smash, and can even use items and taunts without affecting its hitboxes.

When all hits connect in a single character, this Final Smash can rack between 270% and 300%, making Diffusion Beam the most damaging Final Smash in Brawl. However, to deal the full damage, R.O.B. must Grab the opponent right before the hard-hitting beam lands, which is very hard. However, it is possible to make it land when the opponent is grabbed without taking knockback, like if the character autoreleases. Precise timing is crucial in order to deal Diffusion Beam's full damage.

R.O.B.'s Special Moves
Brawl SSBWU/3DS Ultimate
Standard Special Robo Beam
Side Special Arm Rotor
Up Special Robo Burner
Down Special Gyro
Final Smash Diffusion Beam Super Diffusion Beam Guided Robo Beam

Trophy Description

Diffusion Beam Trophy.jpg
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. However, 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, using it right as the bridge becomes solid will make R.O.B. invincible and the noise of the Diffusion Beam will play, although he is not using it. However, using his Gyro will make part of the beam reappear, which will be harmless.
      • If R.O.B. enters the Negative Zone with the Infinite Diffusion Beam, he will take damage and suffer the Negative Zone's effects. If the Negative Zone ends with R.O.B. sleeping, he will remain asleep for an unusually long time.
  • 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).
  • Although he's invincible, he can still be KO'd by the Isaac assist trophy, as well as similar attacks, as they merely move him around.
  • During R.O.B.'s Final Smash, he cannot be hurt by the spikes on custom stages - he will walk on them like they are normal platforms, without gaining any damage.
  • There is a similarly named power-up in the Metroid games. However, its effect is in no way similar.