The Shady House is a dilapidated mansion covered in graffiti and grime. It has two floors, with one of the second story bedrooms serving as Guzma's makeshift throne room. The player must collect three secret passwords from around the mansion and answer a Grunt on the second floor correctly in order to be able to reach Guzma. In Pokémon Sun and Moon, the passwords involve Guzma, while in Pokémon Ultra Sun and Ultra Moon, they involve Plumeria.
If the player sits down on Guzma's chair after defeating him, a Team Skull Grunt will rush in, momentarily mistaking the player for his boss before realizing his mistake and leaving.
Upon entering the second room on the west side of the second floor, the player will observe two female Grunts arguing with one another over mistaking each other's clothing. One of the Grunts offers a solution that they should write their names on the tags. This is immediately dismissed by the other, who notes that they all are named Grunt, defeating the purpose. This is a joke on the fact that no villainous teamGrunts are given unique names, even with the introduction of Trainer names in Generation II.
After defeating Guzma, the player cannot call Charizard Glide until encountering Nanu in front of the Shady House. However, they can travel to Poké Pelago.
In Pokémon Ultra Sun and Ultra Moon, upon entering the room directly north of the front door, there is a chance encounter with a Delibird, who briefly comes down the chimney and into the fireplace, before disappearing into the chimney again, making an allusion to Santa Claus.