increases your Pokémon's Special statistic by an amount equal to its
initial value. Thus, the first use of this attack results in double the
normal Special score. The second use results in triple the normal Special
score, while the third use results in quadruple the normal Special
score. Effects are cumulative for a maximum of three uses. Further uses
have no effect.
Note that like other statistics, Special has a maximum value of 999. If
a use of this attack would raise your Pokémon's Special beyond 999, it
will instead raise it only to that value. If its Special has already
reached 999, this attack will fail.
Also note that since the attacker's Special statistic is being altered,
both the effectiveness of the attacker's Special attacks and resistance to
such attacks, such as Bubblebeam and Vine Whip, will be increased.
Damage caused by and resistance to Physical attacks like Pin Missile and Jump Kick will not be affected.
For more information on the different kinds of attacks and how damage
is determined for each of them, see the Attack Base Explanation.