Iron ball

Iron balls are objects found throughout Pikmin 3 that serve as an interactable tool, much like the cardboard boxes. They are very plain metallic-gray orbs with "20 weight" inscribed on them. As the number would imply, 20 Pikmin are needed to push them. Because there is not enough surface area on the object for 20 Pikmin to push it, some Pikmin will go behind other ones and push them instead.

Iron balls are always placed at the top of a slope, so they will rush down a fixed path once the Pikmin have set one in motion. With its momentum and weight, it will break open walls the Pikmin could not have torn down themselves. This opens entrances and exits to other parts of an area. Creatures in the ball's path will be killed, allowing the player to defeat enemies in some rare cases, but Pikmin (that aren't Rock Pikmin or Winged Pikmin) are more likely to be crushed if the player does not pay attention. As such, it is not advised to have more than 20 Pikmin charge at a ball, as some of them may get in front of it while attempting to find a spot to push on.

Locations

 * Distant Tundra:
 * One is atop the slope where the Yellow Onion is. When it rolls down, it destroys the blockade on the cave's main exit.
 * Another ball serves as the "nose" on the snowman figure of the President. When pushed out, it rolls until it destroys the blocked entrance to the cave with the Pyroclasmic Slooches.


 * Formidable Oak:
 * The room with the bridge and Arachnode has the final ball in Story Mode. When pushed, it rolls down a slope and destroys a crystal wall down below. If there is a bomb rock on the path, it will hit that and explode, but if not, it will instantly disappear when it reaches the wall at the end.


 * Formidable Oak Remix:
 * One stands in the same location in Story Mode. It is next to a Whiptongue Bulborb and beyond it are many Dwarf Bulborbs. It disappears at the end of its path similarly to the one in Story Mode.
 * Another is near the room where Brittany starts and 2 Orange Bulborbs, and destroys a path of Bulborbs and a crystal wall. It disappears at the end of the open room it ends up in, either after defeating the Bulborbs or destroying the eggs.


 * Jigsaw Fortress, layout B:
 * At the top of the fortress, right by the Onion, is an iron ball precariously on a ledge. When pushed, it falls down to the second level, then to the third. It then heads right, circles the third level of the fortress and destroys the brick wall shortly before the starting point. It then circles around once more but veers off to the left before the wall's spot, descending to the lowest level. It then rolls a bit more forward and drops at the hay ledge just before the electric gate. Finally, it proceeds forward for a bit, turns to the left of the building made of blocks, goes over the rim of the stage, stops abruptly after a bit, and then disappears one second later.


 * Rusted Labyrinth, layout C:
 * At the center of the stage is an S-shaped corridor, going downwards, with two brick walls in the middle. There is an iron ball at the start of the corridor that when pushed, goes down the corridor, breaking both walls, and then keeps going towards the bottom player's Onion, slightly off to the right. It then careens off the rim of that Onion's room and disappears shortly after.