When this creature enters, you take the
initiativeThere are three inherent triggered abilities associated with having the initiative. These triggered abilities have no source and are controlled by the player who had the initiative at the time the abilities triggered. This is an exception to rule 113.8. The full text of these abilities are “At the beginning of the upkeep of the player who has the initiative, that player ventures into Undercity,” “Whenever one or more creatures a player controls deal combat damage to the player who has the initiative, the controller of those creatures takes the initiative,” and “Whenever a player takes the initiative, that player ventures into Undercity.” See rule 701.49, “Venture into the Dungeon.” (CR 726.2).
At the beginning of each opponent's upkeep,
untapTo untap a permanent, rotate it back to the upright position from a sideways position. Only tapped permanents can be untapped. (CR 701.26) a creature you control. If you've completed a
dungeonA dungeon card is in the command zone while a player ventures through its rooms. (CR 309),
untapTo untap a permanent, rotate it back to the upright position from a sideways position. Only tapped permanents can be untapped. (CR 701.26) all creatures you control instead.