Cobalt Pikmin are a type of Pikmin who are blue, and are immune against Metal Poisoning. They can be found underground, and they are born from a Cobalt Tree, which can be taken out of the ground. They must stay in a ship though. They are first discovered in Pikmin: Cobalt Frontier.
Pikmin 4: the wraith's revenge
Cobalt Pikmin are laser beam resistant, and look very dark blue, can fire laser beams at enemies, and have Guardian Stalker like adornment atop their heads.