Why can't I use Rock Climb on Torterra on Showdown?

Question

See its like this, I was playing Pokemon Showdown and made this Torterra:

Torterra (M) @ Groundium Z
Ability: Shell Armour
- Crunch
- Earthquake
- Rock Climb
- Frenzy Plant

But then it said that Torterra cannot learn Rock Climb.

Now, I've had some experience with a Torterra that I got in Soul Silver and HE knew Rock Climb. So I know that he can learn it from the HM. Someone told me its because there are no HM's in Sun/Moon.

Answer 1

Your Torterra has shell armor, which is a hidden ability. Hidden abilities are available only on Pokemon originating Generation 5 or later. Torterra can only learn rock climb in Generation 4. Since Pokemon can't be transferred backward, Torterra with shell armor can't learn rock climb.
sou rce
This is kinda off topic, but crunch, frenzy plant, rock climb and groundium Z are not good things to have on a Torterra.

Comments

Thanks. Oh well, what do I know.

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Cool source thing you did.