Known that you must take certain steps to find each a Pokémon with a hidden ability, or an Item or a Hidden Item, the Hidden Grotto can be regenerate can be increased by the use of a Pass Power. Here is a list of what the percentages are to find one of the three things in the Hidden Grotto. * 40% — You will find an Item. * 40% — You will find a Hidden Item. * 20% — You will find a Pokémon with a Hidden Ability.