Psystorm inflicts damage, hitting the target 2-5 times per use with a base power of 25 per strike. There is a 33.3% chance that it will hit 2 times, a 33.3% chance it will hit 3 times, a 16.7% chance it will hit 4 times, and a 16.7% chance it will hit 5 times. Ignoring the possibility of missing, it will hit 3.168 times on average, giving it an average power of 79.2. Each strike made has an equal chance to be a critical hit.
Psystorm may continue attacking after breaking a substitute. Bide and Mirror Coat will only acknowledge the last strike of this move. Bide and Mirror Coat will only acknowledge the last strike of this move.
If a Focus Sash, Focus Band, or Sturdy activates before the last strike is dealt, the following strike will cause the defending Pokémon to faint. A Focus Band can still activate repeatedly to prevent fainting, but each chance is independent of the previous one.
If the target has Weak Armor, each strike will activate it.