So I put together a small little mostly magic single player map that I play on LAN with my significant other and everything's been fine and dandy up until now. I built myself a nether portal, walked through, and was met with the strangest thing: approximately half of the landmass is made up of Dispensers. Yes, like the type that shoot arrows at you in Jungle Temples and such. Shortly after, the game dropped to less than 1 FPS (much, much less) and I have managed to set the game to Peaceful, vacate the Nether, and delete the world file for that dimension (DIM-1 if you're curious), which has restored my FPS back to normal. So the question that remains now is... what in blazes happened? Definitely a new one on me. Here's the basics: 1.7.2 pack with Forge 1149 Applied Energistics 2, rv0-Stable7 BiblioCraft 1.7.1 Blood Magic v1.0.1g Botania 1.1-74 Carpenter's Blocks 3.2.4 Chisel 1.5.4f CodeChickenCore rc1 Enchiridion 1.1a Ender I/O 2.0 beta 123 ForgeMultiPart 220.127.116.114 HopperDucts 1.3 Inventory Tweaks 1.57-116 Iron Chests 18.104.22.1689 Jabba 1.1.3 Light Bridges and Doors v2.0 Mantle 0.2.8 Mariculture b12 Natura 2.2.0a3 NEI rc2 PneumatiCraft 1.2.1 Random Things 2.1 Tinkers' Construct 1.6.0.a14 Thaumcraft 22.214.171.124 Thaumic Pipes (whatever latest is, pretty new) Tinkers' Mechworks 0.2.7 Totemic 0.4.1 VoxelMap 1.0 WAILA 1.5.2-1.7.2 rc2 Witchery 0.19.2 World Generation Manager 0.3.5 That's the list. So far it's largely a copy of Unstable, though a bit more updated and with a few additions to the list. Sadly, my original attempt at Unstable crashed hard enough to corrupt the world, hence my decision to just try modding things by hand. If anyone's seen weird world gen like that, let me know?