Question

I think someone has asked this before but not sure on that.

Comments

Which Pokemon?

Answer 1

Gen IV

If a Pokémon that has become a pure Flying-type uses Roost, it will become a ???-type Pokémon until the end of the turn.

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Gen V

If a pure Flying-type Pokémon uses Roost, it will become Normal-type until the end of the turn.

So no, Ground will not be super-effective. Ground is not super-effective to ??? type or Normal type.

Source

Hope This Helped :D

Comments

thanks

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no prob :D

Answer 2

Depends on what flying type it is, because when you use roost, you loose your flying typing. So that means Earthquake would be super effective on all Flying-Fire, Flying-Electric, Flying-Poison, Flying-Rock, and Flying-Steel, after they have used roost of course.

Comments

so your saying it makes ground neutral on a flying type only pokemon?

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Yes because if it's just plain flying type are Tornadus, and Arceus-Flying, so if Tornadus used Roost, then Earthquake would be Neutral.