Pokémon Bank subscribers can receive a special Decidueye, Incineroar and Primarina from March 9th, 2018 until October 31st, 2018. These Pokémon come with their Hidden Ability and it is the first time that these Pokémon have been distributed with their Hidden Abilities.

A New Bonus for Pokémon Bank Subscribers

Everyone who has registered for Pokémon Bank can get a special Decidueye, Incineroar, and Primarina.

Pokémon Bank is the paid service for your Nintendo 3DS family of systems that allows you to store and transfer your Pokémon online! And for a limited time, if you sign up or are already registered for Pokémon Bank, you'll receive three cool Pokémon originally discovered in the Alola region for your Pokémon Ultra Sun, Pokémon Ultra Moon, Pokémon Sun, or Pokémon Moon game. The three Pokémon will each arrive with a Hidden Ability that is not available through normal gameplay. This is the first chance to get these Pokémon with their Hidden Abilities, making this a special opportunity!

Decidueye's Hidden Ability is Long Reach, an Ability that no other obtainable Pokémon has had before. It allows the Pokémon to use its moves without making contact with its opponents, so Decidueye won't take damage from Abilities like Rough Skin or held items like Rocky Helmet.

Incineroar's Hidden Ability, Intimidate, lowers its opponent's Attack when Incineroar enters battle. With Intimidate, you can cut down on the attacking power of opponents that rely on physical attacks.

Primarina's Liquid Voice Hidden Ability has also never been available for a Pokémon until now. With Liquid Voice, all of Primarina's sound-based moves become Water type. Because these moves become the same type as Primarina, their power is increased!

To receive these Pokémon, become an active Pokémon Bank subscriber by October 31, 2018. The cost for Pokémon Bank is $4.99 for a one-year subscription. You can sign up and download Pokémon Bank via Nintendo eShop.

To receive Decidueye, Incineroar, and Primarina:

1. Start Pokémon Bank and select the game in which you would like to receive the gift.
2. After receiving your gift in Pokémon Bank, start up the game you previously selected.
3. You will receive your Pokémon as a Mystery Gift from the delivery person in any Pokémon Center.
4. Remember to save your game!

Note: You will receive only one trio of Pokémon per Pokémon Bank account.

Source: https://www.pokemon.com/us/pokemon-news/a-new-bonus-for-pokemon-bank-subscribers/