Venture into the dungeon

Venture into the dungeon is a keyword action introduced in Dungeons & Dragons: Adventures in the Forgotten Realms. It interacts with the dungeon card type.
==Description==
Venture into the dungeon can be the effect of a spell, an activated ability, or a triggered ability.
If you venture into the dungeon while you don't have any dungeons in the command zone you put the dungeon of your choice into the command zone and put a venture marker on the first room, at the top. The next time you venture into the dungeon, you'll move to the next room by placing the marker on that room. When you enter a room, the room ability of that room triggers. After the final room ability resolves or otherwise leaves the stack, the dungeon is removed from the game. Removing it from the game results in you completing the dungeon. When you complete a dungeon certain cards receive a bonus. 
The next time you venture into the dungeon, you can choose the very same dungeon you were just in or you can head into a new one. 
===Venture into Undercity===
Venture into the dungeon is a mechanic that will break if you add too many dungeons to it. Commander Legends: Battle for Baldur's Gate therefore introduced the Initiative mechanic, which allows you to enter only a specific dungeon, <c>Undercity</c>, using the Venture into [Quality] variant. However, once you already entered the Undercity, Venture into the dungeon allows you to move further into it. In the same way, Venture into Undercity allows you to move further in any other dungeon if you already entered them.
==Rules==
==Rulings==
*Dungeon cards begin outside the game, and can only be brought into the game by cards that say "venture into the dungeon."
*The player venturing into the dungeon chooses which dungeon they will venture into.
*Dungeon cards are not part of a player's deck or sideboard. Players can use any dungeon they own.
*You can only move forward (downward) in a dungeon, never backwards or sideways.
*Dungeons are removed from the game as a state-based action.
*If you somehow venture into the dungeon while a room's ability is on the stack, you will continue on in the dungeon. If you're already in the last room, complete that dungeon and start a new one.
*Whenever a player ventures into the dungeon, no player can respond until after that player has selected which dungeon to enter and its first room ability has triggered.
*You cannot venture into Undercity unless instructed to do so, either because you have the initiative at the beginning of your upkeep or because you take the initiative. Notably, if you aren't in a dungeon and an effect instructs you to venture into the dungeon (not venture into Undercity), you can't start Undercity.
*Similarly, when instructed to venture into Undercity, you can't start a dungeon that isn't Undercity.
*If you aren't in a dungeon when instructed to venture into Undercity, you will put Undercity into the command zone and move your venture marker to Secret Entrance (the first room).
*If you're already in a dungeon when instructed to venture into Undercity, you move to the next room of that dungeon. If you are already in the last room, you will complete that dungeon and start Undercity. This is true whether you're already in Undercity or any other dungeon.
*If a player's dungeon is destroyed with , that dungeon and its venture marker are removed from the game. Venturing into the dungeon afterwards will cause that player to choose a new dungeon and they will start in the top-most room.
==Background==
Venture in the dungeon is somewhat similar to the unreleased Skirmish mechanic from War of the Spark.
In early design, the venture mechanic used a dungeon deck, sort of similar to the Contraption deck in Unstable, so what room you explored next was randomized.
==References==