In Pokémon 7th gen, the chance of Effect Spore activating is 30%. However, some types like Steel or Electric are immune to some conditions such as Poison or Paralysis.
In this case, if say, Kartana attacks Shiinotic, is the chance of Effect Spore activating 20% (only Paralysis or Sleep), or 30% (Paralysis and Sleep each has a 15% of activating)? How is it calculated?
Best Answer
First off, your percentages are a bit off. According to Bulbapedia, Effect Spore has a 9% chance of inducing poison, 10% chance of inducing paralysis, and 11% chance of inducing sleep.
It doesn't specify what happens when the opponent effected by it is a steel type but I think it's safe to assume that it first determines which effect to trigger and then check if the spore will have effect on the opponent