Dive cancel
A dive cancel refers to diving at a steeply sloped surface to cancel Mario's dive action without actually landing on ground. For slippery surfaces, this requires performing a cap throw just as Mario contacts the slope (which can be buffered), the act of which pushes Mario away from the slope a bit. For other surfaces, Mario's dive will be canceled regardless and he will revert to the falling animation, but it is still generally necessary to throw Cappy during or after the dive cancel to push Mario away from the slope in preparation for another dive.
Because throwing Cappy allows another dive to be performed, it is possible to chain repeated dive cancels to climb certain slopes indefinitely. However, doing this on steep slopes is usually extremely difficult since the amount Mario gets pushed away from the slope after a cap throw is generally inconsistent, and if Mario is too close to the slope when attempting to dive, he will often dive at the wrong angle.
Uses
Various speedruns
In any speedruns that utilize Moon Cave Skip, a single dive cancel can be used to perform a harder variant of the trick known as one-wall-jump Moon Cave Skip. This saves a marginal amount of time over the standard Moon Cave Skip by forgoing the second wall jump in favor of a dive onto a small, sloped section, which can be followed up with a dive cancel to safely reach the top.
Minimum Captures World Peace
In Minimum Captures World Peace speedruns, dive cancels could potentially be used to scale the side of the Luncheon Kingdom volcano in order to perform the captureless variant of Meat Skip. This would likely be significantly faster than the current known method turnip climbing, although still likely slower than the other theoretical method of using slopevaults.
Miscellaneous
In the Magma Swamp level within the Luncheon Kingdom, repeated dive cancels can be used to climb to the top of the tall wall surrounding the level.[1] Some portions of this wall can be stood on, and Mario can traverse the top of the wall by jumping between these portions.
Dive cancels can be used to reach the Warp Painting platform in the Snow Kingdom without jumping from the Odyssey, as is normally required to perform Snow Dram.[2] Since the Odyssey does not exist in the scenarios for Koopa Freerunning or Luigi's Balloon World, the dive cancel method allows the platform to be reached during those minigames; in the case of the latter, this enables a balloon to be placed in a very difficult-to-reach location.
In the Cold Water Dash level in the Snow Kingdom, dive cancels can be used repeatedly in order to climb the large slopes at the end of the level without the use of a Rocket Flower. This makes it possible to collect both moons without picking up any Rocket Flowers.[3]