Chilled-Out Cucumbress

The Chilled-Out Cucumbress is a treasure that is unlocked when the player scans the Marie amiibo from the Splatoon series. It looks just like the amiibo, and is worth.

Collecting the treasure
After scanning the amiibo on the area selection screen (in any sector), the treasure will appear in one of the Secret Spots of the area. Then, the player has to retrieve the Chilled-Out Cucumbress in that spot.

Trivia

 * Olimar brings up the topic of "cool, quiet partners", referring to Marie's role in the Splatoon series, portrayed as the more subdued of the Squid Sisters.
 * He also alludes to the S.S. Dolphin II, who acts as a similar foil to Olimar as Callie does to Marie.