Hatchan's Sea-Floor Stroll

Hatchan's Sea-Floor Stroll (はっちゃんの海底散歩 Hacchan no Kaitei Sanpo) was the 4th Mini-Series created as side stories on the title pages of each One Piece chapter.

Length
ch. 182–228 (40 installments)

Short Summary
Hatchan escapes from a marine ship, where he does several good deeds to redeem himself after his time as a member of the Arlong Pirates. After one of his deeds in killing a sea monster, he meets Camie the mermaid and Pappug the starfish, whom he immediately gives to the Macro Fishman Pirates after they give him a map to a creature that would help him create his favorite dish: takoyaki. Finding nothing after killing the beast and at Pappug's request, Hatchan defeats the Macro Pirates and takes their treasure before discovering the true treasure within the creature: the world's greatest takoyaki sauce. Continuing his journey, he discovers a starving village of catfish, which he decides to help by selling his treasure for cooking equipment and making takoyaki for them, while at the same time making an extra for his girlfriend Octopako. While the female octopus-man turns him down, the catfish are grateful. Hatchan seems depressed at losing his girl, but realizes his true dream is to run a takoyaki stand, which is accomplished thanks to the catfish building a special boat. In the end, he finally accomplishes his dream with Camie by the opening of his new stand: Takoyaki 8.

Chapter Titles

 * 1) Jailbreak (chapter 182)
 * 2) Time to go home (chapter 183)
 * 3) Hatchan saves a Panda Shark (chapter 184)
 * 4) Hatchan gets meat as thanks (chapter 185)
 * 5) Hatchan meets a hungry man (chapter 187)
 * 6) Hatchan gets a ring as thanks (chapter 188)
 * 7) The Goldfish Princess who lost her ring (chapter 189)
 * 8) Hatchan gets a golden trident in thanks (chapter 190)
 * 9) The giant Seaboar being chased by a Sea Monster (chapter 191)
 * 10) Hatchan saves the Seaboar (chapter 192)
 * 11) From inside the Seaboar's mouth comes... (chapter 193)
 * 12) Camie the Mermaid and Pappug the Starfish (chapter 195)
 * 13) The shadow that approaches Hatchi after he saved them from almost being eaten by another fish after being eating by a fish (chapter 196)
 * 14) Introducing the Macro Fishman Pirates (chapter 197)
 * 15) Reunion with the dear old Chums (chapter 199)
 * 16) Suprise Camie!! Deal to the Fishmen for Takoyaki map (chapter 200)
 * 17) Search for the legendary Gekiuma Takoyaki recipe (chapter 202)
 * 18) Prepose one more time to the darling Octopako (chapter 203)
 * 19) At the maps end lies the great Octopus Mash (chapter 204)
 * 20) Hatchi's wrath at being fooled!! (chapter 205)
 * 21) Where are they? (chapter 206)
 * 22) Mermaid selling Maros (chapter 207)
 * 23) Octopus Punch! (chapter 208)
 * 24) You can't trick me! (chapter 209)
 * 25) The best cooking-source found (chapter 210)
 * 26) Both treasures aquired, no one can stop me! (chapter 211)
 * 27) Octopako was out at the moment (chapter 212)
 * 28) Too bad! The headband catfish village crushed by a sinking ship (chapter 214)
 * 29) Hatchi comes to the starving Catfish village (chapter 215)
 * 30) Hatchi's escape! (chapter 216)
 * 31) Save the catfish village! Hatchi turns the treasure into ingredients!  (chapter 217)
 * 32) We're now open, Hatchi's octopus ball stand (chapter 218)
 * 33) The catfish village is now saved, now one last batch to my marriage proposal (chapter 219)
 * 34) Octopako is attracted by the smell of the sauce (chapter 220)
 * 35) The catfish elder who came last (chapter 222)
 * 36) Octopako's punch and elder's smile (chapter 223)
 * 37) Hatchi and the sunset (chapter 224)
 * 38) Under the warmth of the setting sun, remembering the dream of a Takoyaki stand (chapter 225)
 * 39) The catfish village shows its thanks (chapter 227)
 * 40) Grand opening of Takoyaki '8' (chapter 228)