View source for Unknown Dungeon (Mystery Dungeon)

[[File:Unknown Dungeon RTRB.png|thumb|250px|A {{p|Charizard}} exploring the Unknown Dungeon]]
The '''Unknown Dungeon''' (Japanese: '''みちのダンジョン''' ''Unknown Dungeon''), also known as Tag Mode, is a wireless feature of [[Pokémon Mystery Dungeon: Red Rescue Team and Blue Rescue Team|Pokémon Mystery Dungeon: Blue Rescue Team]] that can be activated from the [[main menu]]. The option is unlocked once {{p|Magnemite}} is recruited after clearing [[Mt. Steel]].

When two players of the same language and [[Software region|region]] have this mode on and are close enough to each other, their current leader Pokémon will go into the dungeon while the system is closed. Unlike other dungeons, these outings are completed off-screen without player input. Their Pokémon will "befriend" each other, and will bring an item back from each dungeon explored. Some of these items are otherwise unobtainable. The Unknown Dungeon can be repeated an unlimited number of times.

The Unknown Dungeon can also be used to meet with Link Agents by communicating with a copy of [[Pokémon Trozei!]] of the same language and region in Espionage mode. The Trozei! player can receive a Message Card and prize coins.