Psychic super-effective against ghost type? Could this be a glitch?

Question

So to put it simply, according to the database the problem with overpowered psychic-type Pokemon was fixed in gen 2, and ghost-type moves are supposed to be super effective against psychic-type Pokemon instead of the other way around.

Why was my Gastly ko'd by a Kadabra's super-effective Psybeam? Why did none of Gastly's ghost-type moves have super-effective damage to Kadabra if that's the way it's supposed to be?

I'm just really confused because isn't it supposed to be that ghost is super effective against psychic? I don't know if I misunderstood the database or not, but I would like to find out. Could this be a glitch?

I'm playing Diamond, if that's any help.

Comments

ghost doesn't resist psychic.
poison is weak to psychic
poisson is french for fish
a poisson pokemon is not likely to be weak to psychic, however

Answer 1

Gastly is part Poison type. Psychic straight up kills poison types and because Ghost types take neutral damage from psychic attacks the attack was super effective :)

Comments

But he also said that the ghost moves weren't effective.

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I depends on the move. If Night Shade/ Curse were used, they're not super effective because they do fixed damage. Then there's status moves like Confuse Ray, while being Ghost type, don't inflict damage.

If it was, e.g., Shadow Ball that was used, then it would be a glitch if it didn't do super effective damage against a Kadabra.