Upon using the move, Greninja braces itself and when attacked disappears, replacing itself with a substitute while counterattacking the opponent. The direction the attack comes from can be influenced by holding a direction on the control stick. The substitute that appears can either be a log or the doll that appears when the move is used in the main Pokémon games. Afterwards, the substitute remains on the field for a while and can be attacked to knock it around and damage other players.
In Super Smash Bros. for Nintendo 3DS and Super Smash Bros. for Wii U, the first custom variant for this move is Exploding Attack; while it cannot be used as a counter, Greninja instead automatically disappears and reappears in an explosion. The second is Substitute Ambush, which has Greninja counterattack with a slower but more powerful attack.
The Substitute Doll in Super Smash Bros. Ultimate