I’m sure this mod isn’t maintained anymore, but just want to mention this just in case someone does update it. The current game throws errors when trying to start or load a save with this mod installed.
DEBUG : warnings for type vortex_stone:
invalid revert_to property null
FUNCTION : void Item_factory::check_definitions() const
FILE : src/item_factory.cpp
LINE : 1121
DEBUG : In overmap special "Slime Pit", point [0,0,0], location "never" is invalid.
FUNCTION : void overmap_special::check() const
FILE : src/overmap.cpp
LINE : 986
Full stack trace: https://pastebin.com/wJEKHAmx