Shadow Ball (シャドーボール, Shadow Ball) is Mewtwo's neutral special move in Super Smash Bros. Melee and Super Smash Bros. 4. The move itself consists of Mewtwo concentrating shadow energy into a round ball to toss at opponents. It is its strongest attack, and works as an auto-charge special.
The move begins by charging upon the B button being pressed and can be fired at anytime by pressing B again while charging. The player can save the charge by cancelling it when they push the shield button or left or right on the control stick (the latter results in a roll). Mewtwo can also charge the move in the air, where cancelling it will make Mewtwo drop its charging animation normally as opposed to rolling or shielding.
When a full charge is saved, either Mewtwo's left hand (Melee) or both hands (SSB4) will constantly glow with dark power.
Unlike most auto-charge moves, even when it's fully charged, Mewtwo will still continue to 'charge' it until the player releases it or does a shield/roll cancel. In Melee, a charging Shadow Ball does electric damage and traps an opponent upon contact; in SSB4, it no longer has a hitbox while charging. Once fired, the ball will travel in a wave-shaped path, which makes it hard to aim but equally difficult to avoid. A fully charged Shadow Ball does heavy damage and knockback, and explodes on contact with a surface (though the explosion doesn't do anything).
The move has a considerable amount of recoil, especially when used in mid-air, so one must be careful not to use it too close to the edge. However, this can help with recovery if Mewtwo is facing in the opposite direction of the edge. The recoil causes Mewtwo to slide back about half the length of Flat Zone when it performs this move in midair but lands before the animation is complete.
Mewtwo's forward throw also involves Shadow Balls. Mewtwo will telekinetically throw its opponent forward, then hit them with multiple small Shadow Balls. This throw will at minimum deal 9% damage, but in certain situations, the move can deal up to 18% damage. These Shadow Balls can be SDI'd, reflected, or absorbed.
As with all neutral B attacks, Shadow Ball can be used to change direction in the air. While in the air, one should tap the direction they want to face, and then press B (but not at the same time, as that would result in using Confusion instead). Combined with its ability to be quickly cancelled with a shield button, this technique allows Mewtwo to be even more mobile in the air. It can also be used as a recovery technique, due to allowing Mewtwo to face the other direction so the recoil can send it towards the stage; being the best way to utilize this technique.
The shadow glitch is a glitch exclusive to version 1.0 of Super Smash Bros. Melee. It was discovered by INF8, Veg, and Simna ibn Sind; it allows the Shadow Balls in Mewtwo's forward throw to be caught as items. This requires three characters: one Mewtwo, one character to catch the shadow ball, and one other character to be thrown.
The player must have Mewtwo grab and forward throw another player (this works well with Bowser). Then, they need to make the third character jump and air dodge into the resulting stream of Shadow Balls and press the Z button to catch one. This will not make the normal item-catching sound effect, so the player must look at the character's hands afterward to determine if the attempt was successful.
If the Shadow Ball is thrown, it will freeze the game unless it is quickly recaught.
Special Move customization was added in Super Smash Bros. 4. These are the known variations:
Like the other DLC characters, Mewtwo lacks custom move variations (aside from the glitch ones in 1.0.6).
Shadow Ball is a Ghost-type attack in the Pokémon games. While it was introduced as an actual attack in Generation II, its first appearance is actually the movie Mewtwo Strikes Back, where it is used by Mewtwo. It is available as TM30 in all games since its introduction, and it can be taught to a large variety of Pokémon, including Mewtwo and several other Psychic-types.