ive seen Carbink on youtube with the hidden ability... how can I get one in game and is there a way to get one legittimatly?
You can get Carbink with it's Hidden Ability Sturdy in a Horde Encounter in Reflection Cave.
Note: Carbink will appear as part of a mixed horde with Roggenrola, both Pokémon will be at Level 11. You are also not guaranteed to get Carbink with it's Hidden Ability Sturdy, as it could have it's Normal Ability Clear Body.
Sources: List of Pokémon with released Hidden Abilities in Generation VI | Reflection Cave