Stun


 * For the condition that occurs causing characters to shake back and forth while immobile, see Paralyze.
 * For the effect when a shield is hit, see Shieldstun.
 * "Dizzy" redirects here. For the Smasher, see Smasher:Dizzy.

Being stunned or dazed (referred to as FuraFura in Super Smash Bros. Melees debug menu and in-game files for Brawl, Smash 4 and Ultimate, after the Japanese onomatopoeia for dizziness), an effect known as dizziness' in Brawl, is a special condition that leaves a character immobile for a short period of time.

General properties
A stunned character is dazed for a few seconds and can't perform any actions until the condition ends. Button mashing reduces the duration of the effect, and suffering any amount of knockback ends it prematurely. In Smash 64 and Melee, characters can change to other actions immediately after their stun time ends, which can cause unsuspecting opponents attempting to punish them to get punished themselves instead. From Brawl onward, however, every character has an animation for regaining consciousness after their stun ends (known internally as FuraFuraEnd), which lasts 50 frames in Brawl, and 33 frames from Smash 4 onward, giving players a better visual cue and effectively adding more vulnerability time for the stunned character.

Stun is accompanied by a cartoony tweet sound effect that loops until the condition is stopped, as well as small stars that occasionally pop up around the character's head on top. This sound effect debuted in Melee, and its volume was increased in Brawl. In all games, characters also have a flashing red overlay applied to their model; in Smash 4 and Ultimate, however, this only happens when a character's shield is broken. Also, in Smash 4, a halo of stars appears around a stunned character's head. In Ultimate, the number of stars is reduced to 2, but a solid orange halo appears around the character's head as well.

It is impossible to be stunned while airborne. Possibly as a result, any airborne state induced upon a stunned character will cancel the stunned state immediately and they will enter a normal midair state.

While only a broken shield and a shattered reflector is capable of activating a stun state in Smash 64, Melee introduced a type of hitbox that instantly activates stun, a type that has been used in a small amount of moves throughout the series.

The stun effect is weight independent, but the amount of knockback dealt can still be affected by knockback modifiers and knockback resistance (such as from the Metal Box). A stun effect hitbox will fail to stun the target if it doesn't deal any knockback, or doesn't deal more knockback than the target's armor threshold (such as Bowser's Tough Guy mechanic in Smash 4 and Ultimate). However, stun duration itself is independent of knockback.

Stun time
The formula for stun time varies across games, as well as depending on how the stun is inflicted. From Brawl onward, this does not consider the animation for regaining consciousness, effectively adding more vulnerability on top of the actual stun time.

While a character is stunned, including the animation for regaining consciousness, hitting them with a stunning move does not extend the duration, instead simply causing flinchless damage. From Brawl onward, this applies for 70 additional frames after breaking free from stun. Characters also cannot be stunned in midair; attempting to do so causes the stunning move to inflict standard knockback instead, which in Melee is also the case for using Disable on an already stunned opponent.

Shield break
For a shield break, the formula in Smash 64 and Melee is, where p is the character's damage percent at the time their shield was broken. As a result, unlike other status conditions and stun methods, taking more damage decreases the amount of time a character is subsequently stunned from a shield break, reaching a minimum of 90 frames with at least 400% damage. From Brawl onward, the formula is changed to, reducing it by 90 frames compared to the previous games, and causing characters to immediately regain consciousness after getting up from a shield break if they are at 400% damage or more.

Button mashing reduces the duration of shield break stun by 4 frames per input in Smash 64, and 3 frames per input in later games (5.4 for buttons in Smash 4 and Ultimate, but they cannot be inputted as quickly as stick inputs); compared to other status conditions, this leaves players highly vulnerable during a shield break, even with exceptionally fast mashing.

This formula also applies to having a reflector broken in Smash 64 and Melee, and having 's Belly Super Armor broken in Ultimate. Additionally, in Ultimate, equipping spirits reduces the initial shield break stun frames by an amount equal to the character's Defense stat divided by 50, for a maximum reduction of 200 frames with a Defense of 10,000.

Attacks with the stun effect
In Melee, the only attack that can stun opponents is 's Disable, which uses the formula, rounded down. p is the opponent's percent after Disable hits, while h is a handicap equal to the victim's current rank disadvantage over the attacker (for example, if the victim is placing 4th and the attacker is placing 1st, it is equal to 3). As a result, players that are currently losing will be stunned for less time, and the minimum possible stun time without button mashing can be 96, 81, 66, or 51 frames depending on their rank disadvantage. Button mashing reduces Disable's stun time by 5 frames per input.

In Brawl, attacks that stun opponents use a general formula of, rounded up, with the factors corresponding to the following:
 * h and r are both placing factors much like the one used in Melee, but they make stun time even more variable based on the user and victim's stock difference (or points in a time battle). h (handicap) controls stock deficit, being equal to 0.24 if the user is one stock behind the opponent, and 0.48 with two or more stocks behind. On the other hand, r (rank) controls stock leads, being equal to 1.875 if the user is one stock ahead of the opponent, and 2.7 with two or more stocks ahead.
 * If both characters' stocks (or points) are equal, both factors are equal to 0, simplifying the formula to.
 * To summarize, characters stun opponents for 12 more frames with a -1 difference in stocks (or points), 24 more frames with a -2 difference or lower, 28 less frames with a +1 difference, and 40 less frames with a +2 difference or higher.
 * k is the numerical knockback amount inflicted by the stunning attack, using a weight of 100 for every character.
 * Button mashing reduces stun time by 6 frames per input.

As a result, in addition to characters' rank in a battle being a more important factor for stun time, attacks have increased stun time based on their knockback amount rather than the opponent's percent (though the attack's base damage is a factor in knockback calculation, and thus still relevant to stun time). However, due to Mewtwo getting cut in Brawl, there are no longer any playable characters that can use a stunning move without items (Wario-Man's uncharged Wario Waft can stun, but requires the Smash Ball).

In Smash 4 and Ultimate, the general stun formula is slightly modified to  (or   without the placing factors), increasing stun time by 16 frames relative to Brawl. Button mashing still reduces stun time by 6 frames per input, which is now 10.8 for button inputs due to the altered mashing mechanics, though they cannot be registered as quickly as stick inputs.

Disable (Smash 4 and Ultimate)
Mewtwo returns as a playable character after Brawl, alongside its Disable move, making stun once again part of a playable character's moveset without items. However, Disable uses another formula for its stun duration, separate from the general one. This formula is  in Smash 4, and   in Ultimate, both rounded up; as a result, unlike general stunning moves, the opponent's percent after Disable hits is a factor in its duration alongside the resulting knockback value, and in Smash 4, it is not affected by Mewtwo's placing relative to the opponent.

In Ultimate, the placing factors are also different; h (stock deficit) is equal to 0.2 for a -1 difference, and 0.45 for -2 or lower, while r (stock lead) is equal to 1.2 for a +1 difference, and 1.4 for +2 or higher. As a result, Disable stuns opponents for 4 more frames with a -1 difference in stocks (or points), 8 more frames with a -2 difference or lower, 19 less frames with a +1 difference, and 22 less frames with a +2 difference or higher. Without the placing factors, the formula can be simplified to.

By stage
In Wrecking Crew, getting trapped in a barrel and taking heavy damage will occasionally result in the trapped character being stunned upon breaking out. This can only be done with low-knockback attacks, however.

Trivia

 * is the only character in Brawl to lack the tweeting sound effect while he is stunned. The reason for this unique property is unknown.
 * When Samus is stunned, her Power Suit starts to short-circuit, causing erratic and almost glitch-like movement. The same applies to Dark Samus, even though her "suit" is technically part of her body.
 * In Brawl and Smash 4, the 90 frames used for minimum stun time from a shield break in Smash 64 and Melee are still present in the games' code alongside other shield parameters. This suggests the minimum time was still originally intended to be used, but either did not work due to a coding error or was deprecated.
 * In Super Smash Bros. Ultimate, the Zap-Floor immunity spirits state that the user becomes immune to stun attacks; this is technically incorrect, as it actually prevents users from being paralyzed rather than stunned.
 * In Ultimate, using button mashing to escape the status quicker causes the character's stunned animation play at a faster speed.