|Any level when the mines or skull cavern are in a "[[The Mines#Shrine of Challenge|Dangerous]]" state. Cannot spawn of floors that are a multiple of 5 in the mines.
+
|Any level when the mines are in a "[[The Mines#Shrine of Challenge|Dangerous]]" state. Cannot spawn of floors that are a multiple of 5.
−
|
+
|[[Skull Cavern]] when [[Quests#Skull_Cavern_Invasion|invaded]]