Easter eggs are specially hidden secrets that have been put inside the games on purpose. Normally, these do not affect gameplay and are just for entertainment. This page will also include smaller secrets that do not exactly qualify as Easter eggs. At times, references to other series are considered Easter eggs as well, but those will not be presented on this page for the sake of organization, and will instead be listed here.
A commonly recognized bonus. When / is held down, Olimar will lie down on the floor. Nearby Pikmin will then pick him up, and take him to one of the Onions. When he's sucked in, he will hit the bottom of the Onion, and a light will appear from the large flower on the vessel. It will rise into the air, and explode into a burst of light, similar to fireworks. Nothing else happens. This was removed in Pikmin 2, but the leaders can still lie down and be carried after obtaining the Napsack. It is possible to wake up while being beamed up, at which point Olimar will still hit the Onion, but no fireworks will come out.
Every time the game is turned on, the word "Nintendo" will appear on a completely black screen, and a Pikmin will be heard saying "Pikmin!". However, at rare times, a different sound will play instead. The following instances are known to happen, but the chances of them being chosen are currently unknown:
The cause for these sounds is unknown, but it seems to happen randomly, despite being rumored that it changes according to the buttons pressed.
If the player's leader has Pikmin in his group, and is walking around, there is a high chance the Pikmin will sing or hum something.
Title screen secrets
On the title screen, some buttons perform certain actions:
The Ujadani are small insects that can only be found on specific days, and specific locations, making them a very rare encounter. They can be found on days 31, 61, and so on, and show up at the Wistful Wild.
In certain Pikmin 3 areas, one can find small, well hidden drawings that portray Pikmin. There are ones that show just a Pikmin by itself, and others that show Pikmin near their specialty, such as Red Pikmin near fire, or Rock Pikmin breaking a crystal nodule.
Scattered throughout the game are several instances of text written in a language that can only be assumed to be Koppaite. These messages are written in English, and their purpose varies, but are kept a secret to most players, since they are impossible to decode unless the player knows the cypher. Each character in the Koppaite language actually matches up with one or two Latin letters, which is what makes decoding possible.
In some circumstances, the leaders or Pikmin can sing or hum a small theme:
Secret pellet colors
Although it is unclear whether this is an Easter egg or a glitch, it is possible to see pellets with colors that are unavailable in the game. They can be seen in certain areas using the KopPad's map panning feature.