Adapt Stone

The Adapt Stone is an evolutionary stone introduced in Pokemon WholeOrange and UltraViolet. So far, only two Pokemon are affected by it, one by holding it and the other by having it used on it.

Eevee
Eevee can evolve many different ways by the use of this one stone depending on location. In order for the evolution to be successful, the location corresponding to the desired evolution must be the most recent location out of all the ones that can effect this process that the player visited.
 * Eeveon- Normal, the player's home town
 * Combeon- Fighting, a fighting-type gym
 * Nimbeon- Flying, a flying-type gym
 * Toxeon- Poison, a poison-type gym
 * Burreon- Ground, underground
 * Stoneon- Rock, a cave
 * Insecteon- Bug, a bug-type gym
 * Spireon- Ghost, the Spirit Realm
 * Industreon- Steel, a steel-type gym
 * Draceon- Dragon, a dragon-type gym
 * Soleon- Light, a light-type gym

Soxedy
Soxedy can change form and type if leveled up in certain environments while holding the Adapt Stone. It returns to its normal form if the stone is taken away.
 * Insect Form- alien/bug type, forests
 * Beast Form- alien/dragon type, caves
 * Toxic Form- alien/poison type, sewers

Trivia

 * It is the only evolutionary stone that can either be used on a Pokemon or held by a different one and still have an effect.
 * It is the only evolutionary stone whose results depend on locations.