Nut jumping, also known as infinite nut jumping or the wet nut glitch, is an exploit that allows Mario to gain unlimited height using a large seed that has touched the bottom of any body of water. The trick has gained notoriety for being extremely difficult to repeat for many iterations, meaning very few players have become consistent enough to gain a significant amount of height with the trick.
This glitch only works on game versions 1.1.0 and earlier.
To perform the glitch, the player must first locate one of the large seeds that are used to plant beanstalks (the exploit does not work with small seeds). The seed must then be made "wet" by placing it in a body of water and allowing it to sink to the bottom. Once Mario retrieves the seed, it will have different properties. (If the seed is placed back into water and retrieved before it sinks to the bottom, it will no longer be "wet").
If the seed respawns, it will retain its state, meaning that Mario can dunk the seed in water and wait for it to respawn rather than picking it up from the bottom of the body of water.
Once the seed has been made "wet", it gains a property that allows Mario to catch it in midair. This can be exploited to gain infinite height by repeatedly throwing the seed, diving forward and catching it again. The optimal rhythm for this trick is a triplet rhythm with roughly even spacing: throw, catch, dive, repeat. The catch can be performed either by pressing X or Y in time with the rhythm, or simply holding X or Y from the previous dive input (this is simply a matter of preference). For optimal consistency, the player should not touch the left joystick at all while performing this trick.
The most famous use of the nut jumping exploit is in Minimum Captures runs, most notably Any% Minimum Captures. This trick allows the final wire capture up to the RoboBrood arena in Bowser's Kingdom to be skipped entirely using a large seed that can be found in the Main Courtyard. The most efficient way to do the trick is to throw the seed into the pool at the bottom of the courtyard and wait for it to respawn, eliminating the need to climb back up to the seed's spawn point.
Nut jumping can also be used to climb on top of the ice walls surrounding the Snow Kingdom overworld. Some of these walls have an angle such that Mario can stand in place on top of them. Although nut jumping is not the only way to reach the top of these walls, it is one of the easiest ways to reach one of the surfaces where Mario can stand.