The Power Crouch Stab (also known as PCS) is a term used to describe the behaviour of the 'crouch stab' attack [holding R and pressing B or a sword/stick button] in the Japanese version of Majora's Mask. The quirk itself also exists in every version of Ocarina of Time, you can see the Ocarina of Time page for the Power Crouch Stab here.
The concept is that in the N64 Japanese versions of the game (1.0 and 1.1), the crouch stab attack will have the same attacking power and damage type as the last regular sword or stick attack used, regardless of what weapon is used for the crouch stab.
The following table shows the power of every attack which PCS can copy the power of.
|Great Fairy Sword||4||8|
In the above table, 'Regular Attack' refers to any non-jumplash attack with the weapon.
The following video shows the effect of PCS on a Dodongo (12 health):
Not only does Power Crouch Stab mimic the power of the last attack used, it also has the same damage type as the attack. The damage type describes what effect the weapon has on objects and enemies. This is important to know, as enemies such as Odolwa are immune to deku stick type attacks, so any crouch stab performed after swinging the deku stick will not cause any damage to Odolwa.
When first entering an area or when switching transformations back to human link, the damage type of a crouch stab is always 'null' by default. This means that the sword will hit walls but it will not hit objects and enemies. For this reason, the sword must be slashed at least once before performing a bombchu hover against a wall to ensure that the sword hitbox is able to hit the bombchu as it sticks to the wall, which isn't possible if the damage type of ISG is 'null'.