Pikmin

Pikmin are a plant-animal hybrid 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.

Mario Golf: Toadstool Tour
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 Earth.

Super Smash Bros. Brawl
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. As such, they must be plucked from the ground. When Kirby gets Olimar's ability, he can also use Pikmin, but after plucking them, he immediately throws them.

The Subspace Emissary
A group of Pikmin start to attack a giant R.O.B. which simply rises its arms and spins around knocking them all off and kills most of them. Captain Olimar is shocked and scared, however his Red Pikmin informs him of a new visitor. The Blue Falcon speeds through the forest. Captain Falcon jumps out of the car, and Falcon Punches the robot, sending it flying away. Landing after his attack, captain Falcon accidentally kills many of the Pikmin, but teams up with Olimar, regardless; and the pair run along some old ruins fighting the Subspace Army. They notice an Arwing attacking the ship carrying Donkey Kong: Falco drops Diddy out of his Arwing, and with his Peanut Popguns, the monkey shoots the ship holding Donkey Kong. Captain Falcon and Captain Olimar run to assist.

WarioWare series
Pikmin later appeared in a Pikmin 2 microgame in WarioWare: Smooth Moves, which belonged to 9-Volt. Here, the player controls Empress Bulblax and must roll over all of the Pikmin to squish them before the time runs out. However, it will get harder. The Pikmin will grow larger and start jumping over the player.

In the WarioWare D.I.Y. Microgame Pikmin, the player controls Captain Olimar, who is holding a Red Pikmin in his hand. The point of the game is to throw the Pikmin onto the rock that contains nectar. If time runs out or if the Pikmin is accidentally thrown into the water, the game ends in a loss.

Luigi's Mansion
A trailer for the first pikmin game appears in Luigi's Mansion's option screen. The trailer, predictably, includes the species of the same name.

Trivia

 * A group of Pikmin appears on a Character Card packaged with the Nintendo 3DS, one of five (which also feature Nintendo characters) used with the Augmented Reality Games software.
 * The first three color Pikmin, Red, Blue, and Yellow, resemble the Primary Colors of the color wheel.