Magma Cavern (Japanese: マグマの地底Magma Depths) is the fifteenth dungeon in Pokémon Mystery Dungeon: Red Rescue Team and Blue Rescue Team and Pokémon Mystery Dungeon: Rescue Team DX. It contains 26 total floors and is the penultimate dungeon to be visited during the game's main storyline. The dungeon's first section consists of 23 floors and ends in Magma Cavern Pit (Japanese: マグマの地底最下層Magma Depths - Bottom Layer) which contains a further 3 floors. It is home to Groudon.
Spoiler warning: this article may contain major plot or ending details.
Once the player completes Uproar Forest and finishes at least four missions, Pokémon Square will form a team to rescue Alakazam's team, which hasn't returned. The dungeon will be unlocked once the player finishes at least two missions after that happens and finishes the Team Base.
The visual theme of floors 1 to 7 is normal rock with magma leaking out, for floors 8 to 17 it is hot rock with more magma present, and on floors 18 to 23, the rock becomes blackened with heat, featuring more magma than any other dungeon in the game. In the original games, after floor 23 lies a Kangaskhan Rock and a door that leads to Magma Cavern Pit.
The music in the regular Magma Cavern is unique to this dungeon, and is present on all floors (with the exception of floors 80-89 of Wish Cave).
Gameplay
Generation III
Monster Houses may appear on floors 8-20. Shops may appear on floors 2-6. There is a chance of finding a buried item in floor 1 of Magma Cavern Pit. Darkness shrouds all floors, limiting field of sight to 2 tiles in hallways.
Generation VIII
The boss floor is made of solid rock floating above a layer of magma. When the boss battle starts, the ground shakes, causing the team's Pokémon to be scattered across the floor. Every few turns, magma floods the floor tiles or drains into the ground. Any non-Fire-type Pokémon that touches the magma will get burned.
Magma Cavern was the location where Ginji and Mudkip headed to in order to meet Ninetales and find out if Ginji was truly the cursed human causing natural disasters. They finally reached Magma Cavern in Why I Became a Pokémon. The Answer Finally Revealed!!, but were surprised by the arrival of Team A.C.T., who had come to take Mudkip away from Ginji. Refusing to be taken away, Ginji and Mudkip engaged in a battle against the Gold Rank team, but soon Ninetales arrived, halting the fight. Ninetales then revealed that the real cursed human being was actually Gengar, whose appearance in the Pokémon world was resulting in Groudon's awakening, thus causing all the natural disasters that had happened recently.
In Tears and Emotions - It's the Final Chapter!, Groudon was completely awakened. Gengar revealed that he intended to have Groudon destroy the entire Pokémon world, as said world was the cause of his current state. Groudon, however, didn't listen to him, and almost crushed him under falling rocks, only to be saved by Mudkip. All of Ginji's friends from Pokémon Square, as well as the Absol he and Mudkip had met in Frosty Forest, arrived to their help. Thanks to Gengar, who had finally realized the error of his ways, distracting Groudon with his Double-Edge, everybody got a chance to attack Groudon together, successfully defeating the Continent Pokémon and saving the Pokémon world. Afterwards, Ginji woke up back in the human world.
Trivia
Although NPCs warn the player about Fire types being present in this dungeon, only a small amount of Pokémon in it are part Fire type, with the dominant type instead being Ground.