Pikmin are small, plant-like creatures that play a central role in the 'Pikmin' series. These creatures are discovered by Captain Olimar and are utilized to help him navigate and survive on an alien planet. Each Pikmin type has unique abilities, such as Red Pikmin's fire resistance or Blue Pikmin's ability to survive in water. They are essential for solving puzzles, battling enemies, and collecting items. Their teamwork and various skills are crucial for the player's progress and survival in the series.