All Gens Effect Spore - How does it work?

[george182]

How does effect spore work? There seems to be contradictions all over the internet. Is it the same for every generation?

Feel free to move this thread, I have no idea where it's meant to go.

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Showdown claims:
"30% chance of poison/paralysis/sleep on others making contact with this Pokemon."

This implies that there is a 30% chance of inflicting status, followed by a random selection of each status. So how does this work on poison types, steel types, pokemon with vital spirit etc. Is it still a 30% chance to inflict a status? Will the game try to inflict poison on a poison type and just fail?

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Bulbepdia claims "Effect Spore has a 9% chance of inducing poison, 10% chance of inducing paralysis, and 11% chance of inducing sleep."

This strongly suggests to me each status actually has an 11% chance of activating and it tests the conditions one at a time. So 11% chance of sleep, if fails, 11% chance of paralysis, if fails, 11% chance of poison.

0.89 * 0.89 * 0.89 = 0.704969 (Basically a 70% chance not to get statused).

Obviously because Sleep is first condition tested, it has the higher chance of activating. Meanwhile the actual chance of poison is lower because it won't activate if the pokemon gets slept or paralysed first:
0.11 * 0.89 * 0.89 = 0.087131 (bassically 9%).

If this is the case, how does this work on pokemon with vital spirit. Would the game try to sleep the vital spirit pokemon and then fail. Would this then reduce the odds of it getting paralysed or poisoned, because if the game tries to sleep the pokemon, it won't try to poison or paralyse them. OR does the game count a failed sleep as a failed attempt, increasing the odds of paralysis to 11% and poison to 10%.

This seems like the kind of mechanic that would be improved in future generations.

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How is it actually implemented in showdown?

 

[xJoelituh]

Marty you probably should look this

 

[Marty]

How does effect spore work? There seems to be contradictions all over the internet. Is it the same for every generation?

Effect Spore changed from Gen 3 to 4 and 4 to 5. I've never seen a disassembly of Gen 6 but I assume it's done the same way as Gen 5, unless they caught their mistake.

In Gen 3 it's only a combined 10% chance to activate, and it's done uniformly (1/3 chance for each).

In Gen 4 it's 30% combined, again 1/3 chance for each.

In Gen 5 it's still 30% combined but someone didn't know what they were doing and used greater than instead of less than to determine which status to set, but still used 10 and 20 as the values being compared. This is bad because random numbers start at 0. So instead of rolling a number from 0 to 29 and taking 0-9 sleep, 10-19 paralysis, and 20-29 poison (like in Gen 4), they ended up with 0-10 sleep, 11-20 paralysis, and 21-29 poison, resulting in those skewed probabilities you got from Bulbapedia.

These rolls are done once, so if Effect Spore chooses to status you and then lands on sleep but you have Vital Spirit it just won't do anything and you don't get punished for it. In Gen 6 a Vital Spirit Electabuzz doesn't have any higher or lower chance of Effect Spore attempting to poison it just because it can't become statused by the other two.

This seems like the kind of mechanic that would be improved in future generations.

Haha!

How is it actually implemented in showdown?

For all intents and purposes, PS uses the same probabilities I described above. (Except after looking at it, Gen 4 currently inherits from Gen 5 without re-implementing Effect Spore so I'll have to fix that soon - thanks for bringing this topic up!)