In the core series games
In the Generation V games, the Odd Keystone can be sold to the ore maniac inside the Icirrus City Pokémon Center for 3000.
In Pokémon Diamond, Pearl, and Platinum, an Odd Keystone can be placed in the Hallowed Tower, which is located on Route 209 in the Sinnoh region. This item has no use in other regions.
If the player talks to 32 or more other players in the Sinnoh Underground after placing the Odd Keystone, a wild Spiritomb will be encountered the next time the player inspects the Hallowed Tower. While in theory it is necessary to talk to 32 different players, in practice another player can be counted twice as long as the player themselves leaves the Underground or enters their Secret Base using the "close door and decorate" function between the interactions; this potentially allows a player to encounter Spiritomb by interacting with the same player 32 times.
Once placed in Hallowed Tower, the player can check the Odd Keystone to track their progress. The message gradually changes as the player interacts with more players in the Underground.
| A vital item that is needed to keep a stone tower from collapsing. Voices can be heard from it occasionally.
Spiritomb, with the Odd Keystone visible at the base of its body
The Odd Keystone is clearly visible on Spiritomb's body.
In Pokémon Omega Ruby and Alpha Sapphire, an Odd Keystone appears in the overworld on Sea Mauville. It appears just before the player faces Spiritomb and therefore cannot be collected. Documents aboard the ship reveal it was originally donated by the Oreburgh Mine.
In spin-off games
In the anime
An Odd Keystone in the anime
In The Keystone Pops!, while Ash and Dawn were having a practice battle between Buizel and Aipom, Buizel's Sonic Boom accidentally destroyed the Hallowed Tower, releasing a Spiritomb from the Odd Keystone sealed inside of it. Ash and Pikachu later battled Spiritomb, eventually defeating it and resealing it back into the Odd Keystone, which was then placed back into the rebuilt Hallowed Tower.
In the manga
In other languages