Nectar egg

An egg is a white, semi-round object found in alcoves of caves, and on specific places aboveground. It is unknown if they come from any kind of creature or plant and it may be possible that they are merely egg-shaped containers. They can be attacked, and when broken, they release nectar, although they can also release other spoils. Eggs can be found held by Honeywisps. To destroy an egg, it must be attacked with Pikmin, punched at a few times with a leader, or destroyed by an enemy projectile, like a Gatling Groink's fireworks. It is advisable to throw a Purple Pikmin or similar Pikmin onto an egg, as this will immediately break it and contained Mitites will be instantly defeated. It is also recommended to destroy an egg with a leader, as a Pikmin thrown at the egg may drink the nectar after being called back, wasting it.

Pikmin: Connection of the Worlds
Eggs in this game will wobble a bit if there are Mitites in it.

Pikmin: Wide World
Eggs, when destroyed, produce one to two blobs of nectar that can be consumed by Pikmin or stored in a leader's Spray Bottle. Unlike in Pikmin 2 and Pikmin 3, eggs only yield nectar, not sprays. Eggs that contain Mitites or their relative, Balloon Mitites, will occasionally gently wobble.