Does the ability get changed forever(like if you don't have a hidden ability but a perfect Pokemon will it changed forever?) ? Or is it just temporary?
When used on a Pokémon, this item will change its ability to the other standard ability it can have. If a Pokémon only has one ability, it will not work. It will not change a Pokémon with its Hidden Ability or change a Pokémon to have its Hidden Ability. The effect lasts forever unless that Pokemon faints.