In the core series games, if an Eevee is leveled up in an area containing a Moss Rock, it will evolve into Leafeon. Even if Eevee meets other evolutionary conditions when leveled up, the Moss Rock will still cause it to evolve into Leafeon rather than Espeon, Umbreon, or Sylveon. In Generation VIII, this mechanic was replaced by using a Leaf Stone to evolve Eevee into Leafeon.
In the core series games
- In Sinnoh, a Moss Rock is located in the southwestern section of the Eterna Forest, to the west of a formation of trees that resembles a sideways L.
- In Unova, a Moss Rock is located in the southwestern section of Pinwheel Forest.
- In Kalos, a Moss Rock is located on Route 20.
- In HoennORAS, a Moss Rock is located in the northeast of Petalburg Woods, behind a tree that can be cut.
- In Alola, a Moss Rock is located in the northern section of Lush Jungle, directly north and slightly east of where the player enters.
Eevee will evolve into Leafeon if leveled anywhere in these locations, as long as the player is in the same area as the Moss Rock. Eevee will not evolve into Leafeon if leveled up in the Old Chateau or the path that encompasses the outskirts of Eterna Forest. As the Moss Rock is not present in Kanto or Johto, Eevee cannot evolve into Leafeon at all in HeartGold and SoulSilver; it can only be obtained by trading it from Diamond, Pearl, and Platinum.
In spin-off games
Due to the Moss Rock's absence in Pokémon Mystery Dungeon: Explorers of Time, Darkness and Sky, Eevee evolves into Leafeon through the use of the Mossy Rock. It evolves by the same method in Gates to Infinity.
In Pokémon Conquest
In Pokémon GO
In the manga
In the Pokémon Adventures manga
A Moss Rock appeared in Ring Around the Roserade I. Diamond found one as he, Pearl, and Platinum traveled through Eterna Forest. Liking how cool the stone felt, Diamond, Lax, and Tru decided to take a nap on the Moss Rock, only for Pearl and Chatler to tell them to keep moving.