Spoiler warning: this article may contain major plot or ending details.
It is unlocked after defeating Spiritomb at the Sealed Ruin. Grovyle will accompany the player in the search for Celebi.
When the player first comes across Dusk Forest, the player gets a strange sensation that they have had before which the player later realizes is because Dusk Forest is the future version of Foggy Forest.
The floors are ranked E and S, for purpose of Treasure Boxes and friend rescues.
The first three floors are medium-sized with 3 to 9 rooms, with the other being large sized, generating 3-14 rooms on floor 5, 3-17 on floors 4, 6 and 8, and 3-18 on floor 7. There is 1-4 items on floors 1-3, 2-5 on floors 4-7 and 3-6 on floor 8. There is usually 2-3 starting enemies on each floor.
The IQ Booster activates on every even floor. The turn limit is 1000. The enemies in this dungeon have 26IQ, granting them Status Checker IQ skill. There is light darkness on floors 7 and 8.
The above also describes this dungeon's Special Episode version, where applicable, though the player cannot be rescued if knocked out during the Special Episode.
The geography of the entrance to this dungeon is very similar to the geography of where Wigglytuff's Guild set up camp for their expedition earlier in the game.
This is referenced in the hero's dialogue. When the player reaches camp, the hero notes that it feels like they have been there before. The protagonist later remembers this feeling at Dusk Forest.
The alternate tileset used in the second half of the dungeon is the only one that's used in Special Episode.
