What is the "STABmons" metagame?

Question

Saw Trachy talking about it in his question. Tried looking it up but still a little confused.

Answer 1

All Pokemon can get the moves that they get STAB from. Rotom-W can get Surf and Volt Tackle, for instance.

Also, if a Pokemon changes type while evolving, it gets the moves that the type of its pre evo was. Jolteon can get Shell Smash since Eevee was a Normal type.

Comments

Are they limited to the moves they get STAB from and get from pre-evo only?

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No, the get all their regular moves in addition to all STAB moves.

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Can Eevee get all the moves of its evolutions?

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No, trachy.

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I believe its banned, but hypothetically, could Arceus get every single move, since it can be of every single type?