Do you remember Pikmin 2.5? You don’t. Nobody does.
This video showcases the content of a supposedly unreleased game, Pikmin 2.5, which would take place between 2 and 3.

What we know about the game:
The plot was similar to Pikmin 3, with three characters following Olimar’s path on PNF-404.The main character’s names were Connie, Rodrick and Mike, themed around different land vehicles (Connie – convertible, Rodrick – hot rod, Mike – motorbike). The “themed names” idea would be later brought back in Pikmin 4, where the character’s names were dog-themed.
Green Pikmin were described as “Parasitic”, and could be thrown like a spear. When thrown at an enemy, they lodged themselves into its body taking control over it. They were supposedly the origin of Bulbmin (Green Pikmin infected a Bulborb). Green Pikmin could originally connect together to form a bridge, thought this ability isn’t present in the game itself, and regular bridges appear instead.
Grey Pikmin were covered with hair, so they could withstand cold climate. Aside from that, they were also immune to being eaten, as any enemy would simply cough them out.
Orange Pikmin were very small and weak, though they could walk on walls.
Rock Pikmin would also make an appearance.
Feral Candypop Buds ate the Pikmin that were thrown into it.
Fiery Wollywog might be related to the Young Fiery Wollywog from Hey Pikmin.
Burrowing Snarrow, mentioned in the Burrowing Snagret’s description, would make an appearance as a boss. It would be accompanied by Snachiks (possible inspiration for Pikmin 4’s Downy Snagrets).
Scaredy Slugbug would normally be above ground, but when it saw Pikmin or leaders approaching, it would burrow into the ground, but would later cautiously poke its head out to survey the area. When attacked, it would burrow again to regenerate health.
Shearmites were Sheargrub-like enemies with their name alluding to termites. They could only be damaged by Rock Pikmin.
Fanged Water Dumple was meant to appear in the waters of a jungle-like area, so they probably were like piranhas.
The Sealborb was not actually a seal-like Bulborb, but a seal-like Breadbug, similar to the Dwarf Bulborbs.
Bosses include the aforememntioned Burrowing Snarrow, as well as Shiny Long Legs, Butterbug, Translucent Wollywog, Telescoping Pumphog and Bilious Bulborb. The last three appear as robots in Pikmin Adventure from Nintendo Land, but the Bilious Bulborb is a miniboss, and the Pumphog is a regular enemy.
Because of this, the game might actually be later reworked into Pikmin Adventure.

(this is all fake, I made this video for fun)