A Cappy return cancel, often abbreviated as CRC, is a technique that can be exploited to allow Cappy to gain an extremely large amount of distance away from Mario in two-player mode. This distance can be used to activate Checkpoint Flags, trigger captures, and perform other actions at a great distance. Cappy return cancels were discovered by glitch hunter Syrkl.
In two-player mode, Cappy cannot normally exceed a certain distance away from Mario. However, if Cappy becomes stuck behind something, his path back to Mario will be blocked and he will be able to exceed the normal distance range. In this case, Cappy is in his extended state, meaning that while he will attempt to return to his normal range if there is a clear line of sight, he will simply stay put if there is not.
If the X or Y button is pressed while Cappy is in his extended state, Cappy will enter his returning state and attempt to return to Mario's head. Normally, when Cappy enters his returning state, he will simply fly back to Mario's head. If this is done while Cappy is either stuck behind something or extremely far away, Cappy will not be able to fly back to Mario's head in time and will simply teleport back to Mario after a brief moment (approximately three fourths of a second if stuck, or three seconds if far away).
It is possible to cancel this teleportation in order to revert Cappy back to his extended state. This is what is known as a Cappy return cancel. In order to perform one, the X or Y button must be pressed on Cappy's controller within a five-frame window at the moment that Cappy attempts to teleport back to Mario. Additionally, Mario must be in a certain animation at the moment of the CRC: crouching, rolling, backflips, sideflips, spin jumps, diving, bonking, damage animations, and holding objects all work for this purpose. These animations prevent Mario from showing the animation of placing Cappy back onto his head as he returns. Once the CRC is performed, Cappy will not reappear on Mario’s head, but will instead teleport to another position away from Mario.
While the location Cappy teleports to may seem random at first, it actually follows a consistent geometric rule. Once this rule is learned, it can be exploited to teleport Cappy to arbitrary locations.
The rule depends on the direction Mario is facing, referred to as his "line of sight". This is imagined to be a line that goes through Mario and extends infinitely both in front of and behind him. This line is normally horizontal, but can extend diagonally upward or downward if Mario is standing on a slope.
There are two equivalent geometric interpretations of the rule:
- After the CRC, Cappy will teleport to the location on the line of sight that he is the closest to.
- Draw a sphere such that Mario and Cappy are at exact opposite points of its surface. After the CRC, Cappy will teleport to the far point on the surface of the sphere that is intersected by the line of sight.
The diagrams to the right provide visual explanations of the two rules, and it is evident from the diagrams that both rules describe the same phenomenon.
Mathematically, the rule is described by the following vector formula, where is Mario's position, is Cappy's original position before the CRC, is Cappy's new position after the CRC, and is a unit vector representing the direction Mario is facing:
If a direction is being held on the left joystick on Cappy's controller at the moment of the CRC, the vector will instead be equal to that direction rotated onto the plane Mario is standing on. This is also a unit vector, and must be parallel to the surface Mario is on, meaning that this technique cannot be used to send Cappy to a location that would not be possible from simply angling Mario in the desired direction.
Using the sphere analogy, Cappy return cancels can be abused to send Cappy to distant locations along the imaginary sphere's surface. However, since the size of the sphere depends on the distance between Mario and Cappy, the uses of the trick are limited unless it is possible to get Cappy very far away from Mario. Usually, getting Cappy far enough from Mario requires getting him stuck behind a wall, which would mean that Mario would initially need to walk near that wall to get Cappy stuck. This is often impractical; fortunately, there are a few ways to get Cappy far from Mario without Mario needing to travel to that location.
If any of the four face buttons are pressed on Cappy's controller the exact frame that Cappy becomes controllable (such as after warping to a Checkpoint Flag), Cappy will instantaneously teleport to the Odyssey. When this happens, Cappy will be in his returning state, meaning that a CRC will need to be performed to prevent Cappy from teleporting back to Mario. This is most useful if Cappy gets stuck behind something on his way back to Mario, but if Mario is sufficiently far away from the Odyssey, Cappy can repeatedly ground pound to retain his distance.
Another way to gain distance as Cappy is to repeatedly ground pound into the void many times. Because there is no limit to how many times Cappy can ground pound, Cappy can reach an unlimited vertical distance below Mario.
Normally, the direction that Mario is facing is strictly horizontal. Using the sphere analogy, if Cappy is directly beneath Mario due to repeatedly ground pounding, Mario will be at the very top of the sphere and his line of sight will not intersect any distant point on the sphere. This means that after the CRC, the location that Cappy teleports to will simply be right next to Mario.
However, if Mario is standing on a slope, this direction will point at a diagonal angle, and can intersect a different part of the surface of the sphere. Combined with repeated Cappy ground pounds, slopes allow one to send Cappy an extremely long distance away from Mario. As seen in the diagram to the right, the optimal horizontal distance is achieved when Mario is sloped at a 45-degree angle, and the horizontal distance diminishes the flatter or steeper the angle becomes.
There are two distinct methods that can be used to cancel Cappy's return.
The simplest way to perform a CRC is to press X or Y once to call Cappy back to Mario, then time a second X or Y press to cancel the return at the moment that Cappy attempts to teleport to Mario. After the first button press, Cappy will transition from the extended state to the returning state, while the second press will force him back into the extended state.
For CRCs where Cappy is too far away from Mario, the second button press must occur around three seconds after the first. For CRCs where Cappy is stuck, the interval is approximately 0.75 seconds. Many players use a metronome or beat to assist in timing the second button press, since the window to execute it is only five frames.
This method is useful for setups that involve more than one individual CRC. This is because Cappy ends up in the extended state afterward, giving the player time to adjust Mario's position in preparation for a subsequent CRC.
There is a second method that eliminates the need to perfectly time the second button press. This method is known as the "shake-to-win" or S2W method, and involves repeatedly shaking the controller or mashing the X/Y buttons to cancel Cappy's return.
However, there is a drawback to this method which makes it nonviable for certain setups. When performing a timed CRC, the X or Y button is pressed exactly once to cancel Cappy's return, which causes Cappy to transition from the returning state back to the extended state. However, during a shake-to-win CRC, the repeated inputs will cause Cappy to immediately revert to the returning state again. Therefore, the player will only have around three seconds from that point until Cappy returns to Mario's head, unless Cappy's return is canceled again. For setups that utilize multiple CRCs, this means the player only has a three-second window to properly adjust Mario's position between CRCs.
Furthermore, Cappy cannot perform certain actions such as ground pounding while in the returning state. This means that shake-to-win setups cannot be used for CRCs where Cappy is required to ground pound after teleporting.
Sometimes, Cappy will stay in his current location instead of teleporting. The exact cause of this is not known, but it seems to only occur when there is collision between Mario and the targeted position of Cappy.
It was previously believed that this occurred whenever there was collision between Mario and the targeted position with a surface normal facing away from Mario, meaning that Cappy would not have a clear line of sight back to Mario after the CRC. This became known as the reverse collision theory. However, this theory has been refuted since sometimes a CRC will be successful despite the presence of so-called reverse collision.
While a blocked CRC is normally disadvantageous, it can be useful in some cases to reset Cappy from the returning state to the controllable state without changing his position.
Cappy return cancels are used in various Minimum Captures runs (most notably Minimum Captures Any%) to access Morning Metro to skip the Sherm capture, as well as skip five spark pylons in Bowser's Kingdom. It is also used to make Madame Broode Skip much easier.
Minimum Captures Darker Side
In Minimum Captures Darker Side, a Cappy return cancel is used to skip the Darker Side dungeon by capturing a frog at the end of the level. This is used as an alternative to Frog Airswim on versions where Frog Airswim is not possible.