In the 1999 video game Pokemon Gold/Silver, there is a location in the game known as Azalea Town. It is one of the earlier towns, and the player will typically pay their first visit here within the first few hours of gameplay. However, this town has a unique property.

There are usually 5 central buildings in this town - a Pokemon Centre, Poke Mart, Gym, Charcoal Kiln and Kurt’s House (where the player can obtain custom Poke Balls).

But there is one more house in the town that was thought to have been long discarded at the beta stages of development. The purpose of this building is unknown and it does not have an official name - it has often been disregarded as false memory or a Mandela effect. The truth is that the data for this house is still present on some existing copies of Pokemon Gold/Silver. There are no known methods to consistently spawn the house, but what we do know is that the presence of the house is tied to the save file - if you visit Azalea Town for the first time on a new save and the house is not there, it never will be.

The house is located southeast of the Gym. However, the entrance to the house is mostly blocked off by trees - the only way to gain access to this house is to walk to the far southwest end of the town where a pool of water emerges from the trees.

This L-shaped body of water contains a Whirlpool. This is essentially a roadblock and cannot be passed over unless the player’s Pokemon know the hidden moves Surf and Whirlpool - these hidden moves are not obtained until much later in the game. It is therefore likely that the developers intended for the player to revisit Azalea town once they had obtained these moves to discover the secret of the hidden house.

Sightings of this house are extremely rare, but oddly, the few people who have encountered this phenomenon first-hand all give it the same nickname completely independently of one another. They know it as the Azalea Whirlpool House.