Blue Onion
The blue Onion is the equivalent of a home for Blue Pikmin on the Pikmin planet. In Pikmin 1 it can be found in The Forest Navel in a pool near the landing site, and is the third Onion the player discovers. Several blue Pellet Posies are in the immediate vicinity, as well as a free-standing blue 5 pellet.
In Pikmin 2, the blue Onion is located in the Awakening Wood; although it can be seen relatively early in the game, it lies behind an electric gate, meaning that Yellow Pikmin from the Perplexing Pool are required to access it. A small pool blocks the only direct path up to the gate, so the Pikmin must be thrown onto a nearby ledge (while taking care not to disturb the Cloaking Burrow-nit lying in wait there). The Captain can then walk around through some water to reach them, and order them to defeat the beast and demolish the gate, allowing him to find the game's first 5 Blue Pikmin.