Additional effect
Side-effects are a type of effect of some damaging moves. For example, Thunder has a 30% chance of paralyzing a target.
This does not include primary effects such as recoil, stat penalty or status condition for the user, increased critical hit rate, moves that never miss, moves that change power, two-turn moves, etc. It does include all secondary effects, such as reducing the target's stats, increasing the user's stats, or causing a status condition to the target. Some moves have both a primary and secondary effect. For example, Flare Blitz has both a primary recoil effect and a secondary chance to burn.
Items and abilities are not considered side-effects, but may be negated by Sheer Force if Sheer Force is also negating a move's side-effects. See Sheer Force for more information.