The Anti-hiccup Fungus is a treasure in Pikmin 2, it is found in the Wistful Wild, near the Dream Den. First take some Blue Pikmin, and defeat any hostile enemies near the bridge, including the Cloaking Burrow-nit. Then build the bridge to get your Red/Purple Pikmin to the other side and then use them to kill the Fiery Blowhog, and the Gatling Groink if you haven't done so. Set your White Pikmin to the task of tearing down the wall immersed in poisonous fumes. After that, have a group of Purple Pikmin come and defeat the two Orange Bulborbs and a Withering Blowhog in your path. After they are gone, approach the Dream Den, face the left and you'll see the Anti-hiccup Fungus, which is partially buried.