The autolink angle is a special knockback angle programmed into certain attacks in Super Smash Bros. Brawl and Super Smash Bros. 4. While it reads in the game data as an angle of 363° or 365° degrees, as well as 366° or 367° degrees in Smash 4, the game gives it a special treatment.
The autolink angle works differently for each of its possible angles, though all of them have the same purpose: to ensure opponents will stay trapped by certain multi-hitting moves that cause or require their users to move, almost always through the air. To accomplish this, they usually send opponents in the direction the attacker is moving, with some angles additionally pulling them towards the center of the hitbox that struck them. Examples of such moves where the angle manifests itself are Mario's Super Jump Punch and Falco's forward aerial. It is notably much more common in Smash 4 than Brawl, as many characters with multi-hitting aerial attacks have had these moves adjusted to include it.
The angle does not exist in the original Super Smash Bros. or Super Smash Bros. Melee; all attacks in these games have fixed angles, including those that received the autolink angle in later games. It is typically considered favorable for an attack to employ the autolink angle, as this allows it to connect more reliably and sometimes be used in more versatile ways than one that has a static, unchanging angle; this includes the ability to launch opponents downwards, which causes the autolink angle to be considered a form of unconventional meteor smash.
While not all moves that use autolink angles have set knockback, all of them except those with the 363° angle adjust launch speed using the attacker's distance and (if applicable) the opponent's position, allowing them to still link their hits properly regardless of the opponent's percent. However, hitstun is still determined by the numerical result of knockback, so autolink moves can have low launch speed and high hitstun, rather than them being directly proportional. In Smash 4, as most autolink moves are multi-hit aerial attacks, this trait can be taken advantage of for several kinds of combos, by dragging the opponent long distances down and landing before the non-autolinking hits come out, then hitting the opponent while in hitstun or locking them if the knockback inflicted is high enough to knock them down as they land. Greninja's up aerial is a well known move for exceling at these abilities, as it can be followed up from several moves and bring opponents down to the ground to extend combos farther. Alternatively, this can be done offstage to gimp them very effectively with autolink moves that deal high knockback, such as Luigi's Luigi Cyclone and Fox's forward aerial followed by a footstool jump, which usually take stocks even at very low percents if successful.
In Smash 4, autolink angles have been commonly misconceived as the reason for the first hits of certain multi-hit moves, particularly up specials such as Peach Parasol and Screw Attack, KOing opponents at unnaturally early percents when the attacker has high rage. This actually happens merely due to such moves' first hits usually having high set knockback in order to connect quickly into the other hits as the attacker rises in the air, therefore causing rage to have a much stronger effect on them; in fact, the two examples mentioned lack the autolink angle entirely in their first hits.
The 363° angle is the rarest autolink angle in both Brawl and Smash 4. In Brawl, it is only used for the hitbox enemies in The Subspace Emissary produce upon careening, in order to prevent a chain reaction of said effect when knocking enemies into each other. In Smash 4, it is used for the dashing portion of Lucario's Extreme Speed Attack custom, as well as the windbox produced by the Back Shield when it is hit, and has the effect of launching the opponent in the direction the attacker is moving into, albeit without launch speed modifications. For the former move, this allows Lucario to connect the second hit afterwards regardless of the direction chosen for the first hit, while for the the latter, it ensures characters do not end up too close behind another with a Back Shield equipped. However, in the case of Extreme Speed Attack, the angle still does not account for the move's increase in distance as Lucario's Aura grows, thus making it difficult to link both hits at high percents.
This angle returns in Ultimate, being used in characters' base movesets for the first time. It is used in Duck Hunt's up air, Lucas' down air and Skyward Slash Dash.
The 365° angle is the only autolink angle present in playable character moves in Brawl, and a relatively uncommon angle in Smash 4. Compared to 363°, it sets the opponent's launch speed to 50% of the attacker's momentum, effectively keeping them closer to the attacker as they move in a given direction, and regardless of the knockback caused by the attack. However, the angle still does not function very efficiently, as it disregards how close or far from the center of the hitbox the opponent is. As a result, moves using this angle can be easily escaped with SDI, especially in Brawl where the technique is much stronger.
367° (366° in Smash 4)
The 367° angle was introduced in Smash 4, where it is by far the most common autolink angle, present in a majority of playable characters' aerial multi-hit moves. This angle's function is much more sophisticated than its predecessors', as the direction the opponent is sent in is determined by both the direction the attacker is moving in, and the position of the opponent relative to the hitbox; for example, if they are in the upper end of the hitbox, and the attacker is not moving, they will be sent down and towards the center of the hitbox. This is achieved by setting the opponent's launch speed to the attacker momentum, minus 20% of the difference between the hitbox and opponent's positional coordinates, so like the 365° angle, it allows multiple hits to link properly even if they do not have set knockback. Additionally, this is calculated after hitlag is over. Combined with the weakening of SDI in Smash 4, these factors make autolink moves with the 366° angle impossible to escape under most circumstances.
However, this angle still has some restrictions that, albeit avoidable, may prevent moves from connecting all hits:
366° (367° in Smash 4)
Introduced in Smash 4, the 366° angle is far less common than 367°, but still more so than 365°. It works similarly to 366° in that it launches opponents in the direction the attacker is moving into while also pulling them towards the center of the hitbox. However, it does not reduce the launch speed obtained from knockback, and its "vortex" effect only lasts for 5 frames, after which the opponent's launch direction exclusively matches that of the attacker's movement at the time the hit took place. It also does not have any caps for launch speed, nor it launches grounded opponents at a fixed angle. These properties make moves using the angle much more consistent against grounded opponents, and allow them to connect more effectively for characters that move fast in a certain orientation, such as Falco, whose vertical speed synergizes well with the angle for his neutral aerial. However, the angle's linking ability becomes worse if the attacker's movement is too versatile, due to its momentum-changing quirk, or if a move causes too much knockback, since its launch speed is not modified to compensate: an example of this is Lucas's neutral aerial, whose hits at very high percents erratically launch opponents around him and become very hard to connect, whereas a move using the 367° angle would keep them close more effectively.
Introduced in Ultimate, the 368˚ angle is the newest autolink angle known to exist. Its behaviour is currently unknown however.
For moves without any specification, the autolink angle is present in all their hits except the final one and landing hits.