secretly adding cave

I tried to do a lil spooky prank on Ian, It was a lot harder than I thought Cave dweller mod: Mods in this : True Darkness AI Improvements Alex s Mobs Appleskin Biome s O Plenty Cave Dweller Cave Noises Clumps Essential JEI Lootr Macaw s Bridges Nightmare Epic Siege Nyf s Spiders Sound Physics Remastered TerraBlender YUNG s Better Dungeons