Iron hall is the final cave in Frigid Peaks. getting to it requires all 8 pikmin types. It's in a corridor with a loose soil tunnel blocking the entrance were you will need Brown Pikmin. There is a pool of water behind it with a few Wogpoles. with Blue Pikmin, you will want to drain it out with the drain in the center of the lake. Afterwards, There will be a fire gate with an Electric Gate behind it. There will be a muddy water lake behind that were you will need to make a bridge across. Behind that is a poison gate. You need to use purple pikmin to deflate a bag that needs 1000 pikmin to deflate. (this is actually easier in Pikmin 3, since Purple Pikmin have an Onion now allowing for faster collection of pikmin.) Behind this, the cave entrance is in site, BUT, a series of smoke emitters stands in the way. If you destroy these, you can enter Iron Hall...
Floor 1 is a rusty old pipe with several smaller pipes branching off to pools or gravel beds. In the largest pond, you face a horde of Purple Wollywogs and a Sucking Blowhog. Occasionally, if you disturb the shoots lining the edge of the pool, some Albino Wogpoles will pop out. When you kill a random one, the Crawling Stick will be uncovered. However, when trying to bring it back to the onion, Caustic Dweevils will fall from the ceiling and try to take it. On the one gravel pit, There is the exit. There ARE two other treasures on this floor, but how to get them is not worth noting.
You land on a small, rusty, metal platform surrounded on all sides by muddy water. You should continue with caution, as the surrounding water has Sand Dumples, Sandy Dweevils, and the occasional Maced Bloyster. When making your way around this area, you will want to head to the back of the floor, and there will be a metal arena in the shape of a square. In here, you fight the Hermizad. However, unlike the normal fight for this beast, you will not be able to use bomb rocks. Normally, Pikmin are unable to walk on the Hermizad's pit. However, Tan Pikmin can. You will want to throw a pikmin into the pit and call it back quickly. If you do it fast enough, the hermizad will fail to grab the pikmin and instead crawl out of its pit. It will realize the danger after about 2 seconds, so attacking now is crucial. stay away from the center of the pit, since once it gets back into the pit, it will almost immediately be able to attack. On the original fight with this beast, This is impossible thanks to clever coding to make this battle even more difficult.
On floor four, there is shallow water trickling into a small drain that the pod lands over. There are Violet Candypop Buds near the sources.
contains a trio of golden candypop buds and a geyser.
A metal box with pipes that have various electric and acidic hazards. Enemies include Vomiting Blowhogs, Anode Beetles, Anode Dweevils, and an Electric Blowhog that contains a treasure known as the Superconductor.
This level looks like a metal box that gradually gets a redder color as if heated. There are many fire geysers and Fiery Blowhogs. This floor is more of a maze; its a bunch of tubes that all connect to each other and all eventually connect to the central box. A Fiery Bulblax holds the Worthless Treasure.
This floor has various Poison Hazards. There is a Smoky Progg that will fall from the sky if you enter the center of the map. This map looks like five spheres like before connected to each other. You can also find a few Munge Dweevils if you find treasure and attempt to bring it back to the ship. All the treasure are underground except for the Metal Jaw.
This floor looks like a large, rusty, metal bucket with dirt covering the way out. If break open the dirt tunnel, there will be a pair of Decorated Cannon Beetles. There are Mandiblards scattered throughout these rooms who have all their entrances blocked off by dirt. The exit is also in a dirt pit.
This floor contains a geyser, Three Queen Candypop Buds, and a pair of all Umber, Sandy, Ebony, Violet, and Ivory candypop buds.
This floor is a huge Metal dish, similar to the Titan Dweevil arena, but larger. When you enter a sound similar to a Gatling Groink (only deeper) can be heard, and one of their ammunition will fly from off-screen and grow into the Gargantuan Groink. This beast will flash different colors depending on the means of defense. It has twice as much health as the Raging Long Legs. It will shoot bullets at you, but its gargantuan size means that it cannot move from its spot. When killed, it drops the Mysterious Grail which is worth 5,000 pokos.