One Piece: Kobiyama Who Looks Like Koby - Two Piece in a Pod

One Piece: Kobiyama Who Looks Like Koby - Two Piece in a Pod (コビー似の小日山~ウリふたつなぎの大秘宝) is a spinoff manga of One Piece that was published electronically on the Shonen Jump+ website and app, as well as the official One Piece website, in June 2018. Its first physical volume was published in December 2018.

Premise
The story focuses on Kobiyama, a middle school student who heavily resembles a younger Koby.