The move allows Greninja to suddenly disappear and reappear to ambush foes. The longer the button is held down, the greater the distance, and Greninja can still move about freely, jump, and even taunt, but cannot dash, attack (except for its down taunt), shield, or grab.
When performed, a duplicate of Greninja's shadow on the floor will move forward as long as the button is pressed. Should Greninja move while the shadow creeps forward, the shadow will move relative to its position. Releasing the button will teleport Greninja to the shadow, doing a quick kick upon reappearing. If the player holds the control stick or directional pad forward as Greninja reappears, Greninja will perform a frontal backflip kick that does 10%. However if the player holds in the opposite direction as Greninja reappears, Greninja will perform a back bounce-off kick that does 12% damage and slightly stronger knockback.
Due to the shadow being the only indicator, performing the move in the air, on a stage where the shadow is less visible (e.g. Pictochat 2) or when the stage is tilted in a way so that the floor is not visible makes timing the move more difficult, but also works as a mindgame as a player opponent might also have difficulty seeing the shadow. The shadow is also more subtle in Super Smash Bros. for Wii U than Super Smash Bros. for 3DS.
If Greninja is on flat ground, the shadow cannot be moved onto a slope, or vice versa.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
Introduced in Generation IV, Shadow Sneak is a physical Ghost-type attack. Essentially, it is a Ghost-type variation of Quick Attack, as it is identical in function in all ways including having a priority of +1.
Greninja is capable of learning Shadow Sneak, but at level 23, long before it evolves, so it requires the Move Reminder to learn it.