Confusion (ねんりき, Mindpower) is Mewtwo's side special move. Mewtwo psychokinetically whirls the opponent in front of it around and lets the opponent land clumsily on the ground, doing some damage in the process.
Confusion's primary function is as a command grab. Upon using the move, Mewtwo will perform a swiping motion, creating a purple ripple in front of it; any opponent in range will be grabbed, twirled around in the air, dealt damage and released without knockback in a tumbling state (facing away from Mewtwo in Melee and towards Mewtwo in SSB4 onwards). As a grab, the move is unblockable.
Confusion's secondary function is as a reflector. In Melee, it is unique in a rather detrimental way: reflected projectiles remain the property of their original owner, so Mewtwo cannot actually damage opponents by reflecting their projectiles (unless the projectile can normally hurt its owner). This was changed in SSB4; Confusion now functions as a standard reflector, and reflected projectiles are now able to hit their original owners.
Confusion can execute both of its functions simultaneously if both a projectile and an opponent are in range of the move. For example, Mario's Fireball can be reflected back onto him at the same time as Confusion spins him around, which can cause odd interactions depending on the order in which the grab and reflect are performed. In Melee, this can cause the Soul breaker glitch if the projectile is too strong to be reflected, causing the spun opponent to be indefinitely attached to Mewtwo until it is KO'd.
Using Confusion in the air the first time will provide a small vertical boost, allowing Mewtwo to stall in the air in a similar fashion to Mario's Cape and adding to its already impressive aerial maneuverability. In SSB4, this is combined with a sizable horizontal boost in the direction that the move is performed, making it even more effective as a recovery option and landing mixup; combined with Mewtwo's notoriously flexible airdodge in that game, it was a major contributing factor to its extreme evasiveness in disadvantage. Like the majority of special moves with this stalling ability, subsequent uses of Confusion do not grant any aerial boost, although a quirk in the mechanics of Mewtwo's unique double jump allows it to be used before the apex of its double jump and actually gain vertical momentum from it.
In Melee, Confusion holds the opponent at a distance from Mewtwo as it falls downwards. As characters being thrown are not checked for terrain collision, this opens up a gimmick where Mewtwo can use Confusion to pull opponents down through solid thin platforms, most notably the sides of Battlefield. If done correctly, the opponent will be caught underneath the stage, which can cause them to panic, waste their double jump and/or triple jump, and be unable to recover. If the platform is too thick, the opponent will be pushed outside the stage and likely grab onto the edge.
Overall, while the "edge trick" is something that opponents must be wary of, Confusion is widely considered a poor and ineffective move in Melee. While its grab range is surprisingly large, it is outclassed by Mewtwo's normal throws (for damage, combos, and KOs) and powershielding (for reflection); even if the move connects, every character in the game can subsequently punish Mewtwo with a back aerial during its ending lag. However, SSB4 improved the move's utility greatly; it is no longer as punishable, and as a move which both reflects projectiles and stops opponents in their tracks, it is fairly effective for disrupting approaches or setting up attacks.
In Ultimate, Confusion keeps the opponent in hitstun for slightly longer periods of time based on their percent. As the opponent's percent increases in specific, somewhat arbitrary increments, they will be unable to act for a frame longer each time - up to a maximum of 6 frames after Mewtwo can act out of the move - at 140% and above. This opens up for a few potential mixups not present in SSB4, but the most notable consequence of the change by far is the enabling of a near-inescapable KO confirm in forward aerial when done in the air; as forward aerial has only 7 frames of startup, the opponent must possess a frame 1 escape option, like Pokemon Change or Bat Within, in order to avoid being KOed. This makes it even riskier to shield against Mewtwo at KO percentages, as it now possesses a forward-facing KO option as an alternative to its extremely powerful up and back throws, along with being able to threaten opponents shielding on platforms above it.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
Like the other DLC characters, Mewtwo lacks custom move variations (aside from the glitch ones in 1.0.6).
Confusion is a special Psychic-type attack from the Pokémon series that was introduced in Generation I. It is often learned by Psychic-type Pokémon at low levels, considering the move's weak power, and has a small chance of confusing the opponent (hence its name). In all games, Mewtwo is able to learn Confusion at level 1, though it requires a Move Reminder to actually learn it after being caught since the Pokémon is usually encountered at much higher levels.
In the anime, Confusion could be used to halt and throw a Pokémon or a projectile through telekinetic powers, resembling its effect in Smash.