Swagger increases the Attack stat of the opposing pokemon by 2 steps (termed BTLs in the Gameboy description) on the Stat growth scale, then causes that pokemon to become Confused.
Because of the uniformity of the increases of the value, this increase translates into an increase equivalent to the original value of the Attack stat each time this move is used. In more definite terms, starting with no modifiers, the 1st use of the move will make the Attack stat 2 times the original value, the 2nd will make it 3 times, and the 3rd will make it 4 times the original value.
Swagger will always fail if it has already been used 3 times on the same pokemon, without a move that lowers Attack being used on or against the pokemon that has been affected by Swagger. This is due to the fact that a stat may only be raised by a maximum of 6 steps, until it is reset by the use of Haze or the pokemon is switched out normally. In the case of Swagger, the ability to cause Confusion in the opposing pokemon is the secondary effect and only works if the primary effect is successfully executed (this is much like an attack that causes damage and inflicts a status condition failing because it hits a pokemon that is immune to the damage of that type of attack).
It is important to note that an opposing pokemon who cannot be affected by the secondary Confusion effect (because they are already Confused or have a Safeguard or Substitute in effect) can still have their Attack stat raised, if it is not already at the 6 step limit.
Swagger is affected by Brightpowder when the opposing pokémon is equipped with it.
