Minecraft wiki entry for Advancement_guide, associated text: If you don't have an igloo near your spawn, your best bet to gather these supplies would be to go in the Nether and gather ingredients for a brewing stand and then for a splash potion of weakness. If you really want an igloo, or you can't gather the supplies from the Nether, but don't have an igloo near spawn, you can go exploring and try looking for one. If you have igloos near your spawn, about half of them have a basement underneath them, supplying not only all the ingredients needed to cure a zombie villager, but also a zombie villager itself.