Stale-Move Negation refers to moves causing less damage as they are used repeatedly.
Masahiro Sakurai added stale-move negation to the Super Smash Bros. series in order to encourage players to try different attacks out and use characters to their fullest instead of using the same attack over and over again. When a character uses an attack too many times, the damage and knockback goes down until it becomes less than half its original power. This is something to remember in the Home-Run contest, as some combos will get weaker and weaker. Using different attacks will reset the damage of the spammed attack at about the same rate it was cut, while being KO'd resets all a character's moves.
In Super Smash Bros., stale-move negation affected both damage and knockback. Here, damage and knockback decrease to 75% of their original power and remain constant from that point on (given the attack power is 4% or higher). In Super Smash Bros. Melee, special attacks suffered both reduced damage and knockback, while all other moves only suffered reduced damage. In Super Smash Bros. Brawl, the effect affects both damage and knockback for all moves.
It's worth noting that the effect of Stale Move Negation is considerably stronger in Brawl than in Melee, a fact which a number of smashers have criticised.
In Super Smash Bros. Melee, there is an anti-bonus named "Stale Moves" and is worth -2000.
Testing to determine the stale-move negation effect in Brawl initially confused players, as the effect is not applied in Brawl's training mode (the confusion stemming from the fact that is was applied in the training modes of SSB and SSBM), in fact it isn't applied in Boss Battles Mode, The Waiting Room and the rest area of All-Star Mode.
In Brawl, Stale-Move Negation is calculated with the aid of a queue of the last ten moves a character has connected with. When a move is used that's in the queue, its damage is decreased an amount based on both how often the move is in the queue and how recently the move has been used. If a move is used ten times in a row, it will have lost 55% of its power in total.
Moves that are counterattacks or absorbers do not take the stale-move negation of the incoming attack into consideration.
For some reason, certain moves aren't affected by stale-move negation:
- All self-damage:
- A Judge number 1 always does 12% to Mr. Game and Watch (only in Brawl)
- A fully charged Flare Blade always does 10% to Roy
- A fully charged Eruption always does 10% to Ike
- A fully charged Jet Hammer always does 1% every second to King Dedede until you reach 150%
- Crashing into something while using Diddy Kong's Rocketbarrel Boost always does 5% to Diddy
- Every electric attack does 1%-4% to Pichu
- Hoop damage
- Snake's Hand Grenade's explosion (always 12%-13%)
- Donkey Kong's Cargo Throw (always 6%)
- Donkey Kong's Forward Throw (always 8%)
- The Clawshot used in mid-air (always 4% first hit, 6% second hit if angled correctly)
- The Hookshot used in mid-air (always 4%)
- The Grapple Beam used in mid-air (always 4%, always 7% if tipped)
- Zero Suit Samus's Neutral Air. (always 10%)
- Luigi's Down Taunt (always 1%, in SSB and SSBM, always 2% in SSBB)
Additionally, Brawl+ removes Stale Move Negation entirely.