Me and a buddy are looking at doing something of an underground vault challenge and want some suggestions for a good mod that would make the above ground world something of a hellscape so that there would be a strong incentive to avoid going above ground at all costs. Like for example, I remember a long time ago seeing a showcase for a zombie/creeper apocalypse mod that gives you one full day to gather as much resources as possible and then a perpetual night was unleashed with massive swarms of zombies or creepers. Does anybody know the name of that mod? Because I sure as hell cant remember it and I would love to use that mod or something like it. Any other suggestions would be appreciated for mods we could use.