In Pikmin 4, the organisation are tasked with rescuing reoccurring series protagonist Captain Olimar after crash landing on planet PNF-404.

In Pikmin 4, Oatchi can be commanded by the player to perform tasks to aid in exploring such as destroying obstacles, carrying items and defeating enemies.

He has a yellow coat of fur, a tail with a white ball at the end that resembles a dandelion's seedhead, and lacks a visible nose.

In the game's story, Moss acts as an opponent to the player and Oatchi, who kidnaps castaways along with the protagonist Captain Olimar.

[6] The character of Oatchi was created as a result of the series' low sales, causing developers to consider ideas for a new selling point for Pikmin 4 for both gameplay and being eye-catching.

[7] Developers started to find it difficult to justify having the player control an enemy, so they instead tried to have a character be more associated with the game's narrative of rescuing Olimar.

The idea of "rescue dogs" came to mind with developers, which lead to the decision to add Oatchi as a partner to the player character.

[14] Oatchi is able to be commanded by the player to perform a variety of tasks similar to Pikmin; such as being able to carry objects, attacking enemies and breaking structures.

[16] Additionally, Oatchi can be commanded to charge; either to travel more quickly for a short distance or to bash into breakable objects and enemies.

[21] They end up finding the necessary ingredients after battling and defeating a giant dog-like creature, which had the DNA able to create a cure for Oatchi in order for them to return to space.

[25] Following his appearance in Pikmin 4, Oatchi garnered largely positive reception from critics, with publications such as IGN Japan, Nintendo Life and Destructoid declaring him as one of the best video game characters of 2023.

[28][14] When discussing Oatchi in IGN Japan's character awards for 2023, Takuya Watanabe commented that they thought he was reliable and memorable.

[30][17] Writer Kelsey Raynor from VG247 wrote how they thought Oatchi was adorable, but commented that he looked bizarre and rather strange-looking due to his lack of a nose.

Nintendo Life writer Jim Norman responded positively to the abilities, noting how Oatchi became his only form of transport in the game due to how efficient he was.

[21] Critics from both Real Sound and Eurogamer jokingly commented that the game should have been named after Oatchi instead of the Pikmin due to his ubiquitous role in the narrative.

In July 2023, Japanese manufacturing company San-Ei Boeki announced a seven inch tall Oatchi plushie would be released on Amazon Japan the following September.