Pikmin

Pikmin are a plant species and the namesake of the video game series, Pikmin. They have cameoed in Mario games twice thus far, but their main role is in Super Smash Bros. Brawl, where they are assistants to Captain Olimar.

Super Smash Bros. series
Pikmin serve Captain Olimar in Super Smash Bros. Brawl. Although they are technically not playable, Olimar is almost completely helpless without them, for they are featured in all of Olimar's Special Moves, and presumably some of his Smash Attacks. As such, they must be plucked from the ground.

Super Smash Bros. Melee
''These strange beings are part plant, part animal. They spend most of their time buried in the earth, but they will befriend whoever plucks them, as evidenced by their devotion to Captain Olimar. Each Pikmin has a leaf on its head that grows into a bud and finally a flower. Like a flower, the life of a Pikmin is both fragile and beautiful.''

Cameos
The Pikmin's first appearance in the Mario series was in Mario Golf: Toadstool Tour. Here, if the golf ball landed in a patch of flowers, Pikmin would pop out. This implies that Pikmin may live in the Mushroom World, in addition to the Pikmin Planet.

They later appeared in a Pikmin 2 Microgame in WarioWare: Smooth Moves, which, obviously, belonged to 9-Volt. Here, the player controls Empress Bulblax and must roll over all of the Pikmin to squish them.