Chopper Man

In a short, one-shot story by Eiichiro Oda, entitled Chopper Man, Chopper is depicted as a superhero, with members of the Straw Hat Pirates featured in various different roles (mostly villains). The story parodies the superhero, and super sentai genres, as well as One Piece itself.

Chopper Man, originally created for the One Piece Blue: Grand Data File, had later appearances in Chopper's Grand Battle 3 ending, the omake was originally published in The 6th Log: "Arabasta" in March 31, 2006, the colorspread for chapter 405, and then finally in the first Mugiwara Theater short, which aired with episode 279.

4 Koma chapter
A giant robot attacks the city, forcing the people to turn to Chopper Man to save them. But when Chopper Man decides to imagine himself riding the robot instead of fighting it, nothing gets done.

Chopper Man (Mugiwara Theater)
The evil Dr. Usodabada (Usopp), fed up with being unable to defeat Chopper Man (Chopper), sends his minions to capture Chopper Man's assistant, Namifia (Nami). However, they instead bring back Chopper Man himself. Once there, he demands tea, and then procedes to go see Usodabada's giant fighting robot, Giant Luffy Bomber (Luffy).

Chopper Man rides in Luffy Bomber, and ends up destroying Usodabada's base, sending the villain and his minions flying. This is the only appearance of Robiflowan (Robin), a mysterious flower-woman who has been defeated multiple times by Chopper Man's "Kyuun Spark" attack, Zorogilla (Zoro), a mysterious onigiri-man who demands riceballs and gets angry if you don't have any, and Sanjirops (Sanji), a mysterious perverted-monster who insists he isn't perverted (despite the fact that he constantly thinks perverted things) and shows no mercy to men.

After destroying the base, Chopper Man brings the robot home. However, when he goes to get it for his next mission, he finds that Namifia has sold it.

Characters
The characters are as follows:

Chopper Man
Chopper Man (チョッパーマン, Choppā man) the hero of the story, who uses his Chopper Cape to fly and save the world. Although he can fly with the cape, he also has a private jet, called Air Force C but doesn't ride in it as its just a model. His ultimate weapon is his cuteness, which he uses through his ultimate attack, the "Kyuun Spark". If his enemy doesn't care about cuteness, he will resort to "Chopper Violence". He is obsessed with giant robots, particularly those used by the enemy to wreck havoc on innocent civilians.

Namifia
Namifia (ナミフィア) is Chopper Man's "lovely assistant", who is based on Nami. Resembling a secretary, with glasses and a wireless headset, she appears to be Chopper Man's manager. Namifia is greedy like her alter ego.

Dr. Usodabada
Dr. Usodabada (Dr．ウソダバダ, Dokutā Usodabada) the main villain and "embodiment of evil", based on Usopp. Aside from looking exactly like Usopp, Dr. Usodabada is dressed in a doctor's coat, with a cape, and a handlebar mustache. He resides in an evil castle, with comically bent towers, with cliché lightning crashing behind it. Athought he acts much as his alter ego, he is still humorous

Giant Luffy Bomber
Giant Luffy Bomber (ジャイアントルフィボンバー, Jaianto Rufi Bonbā) based on Monkey D. Luffy, is a giant robot with height 50 meters, stationed outside of Dr. Usodabada's castle, and acts as his secret, ultimate weapon. In the story, however, Chopper Man befriends it, and the Luffy bomber destroys Usodabada's castle. The Luffy Bomber appears to be covered in various guns, a possible reference to his attack names. Namifia sold it for jewelery but later got a refund so the Luffy Bomber could fight the FranDasher.

Usodabadan Three Villains
Although they never appear in the story, they are referenced in the intro. One of them resembles Sanji in a lizard suit, called Perverted Monster, Sanjirops (エロ怪獣・サンジロプス, Ero Kaijū Sanjiropusu). He claims he is not a pervert but thinks about perverted things and has three cigarettes. Zoro is represented as a monster with a fundoshi, the number "1111" across his chest (which could be two "11"s), a metal nose similar to Franky's, and an onigiri for a head (an obvious play on his signature attack), named Onigiri Mystery Man, Zorogilla (おにぎり怪人 ｿﾞﾛｷﾞラｰ, Onigiri Kaijin Zorogirā). Robin is shown as a scantly clad warrior queen, named Flower Mystery Woman, Robiflowan (あ花怪人ロビフラワン, Hana Kaijin Robifurawan), with six arms, and large flower petals adorning her helmet. She is always affected by the Kyuun Spark.

Special episode
Chopper Man reappeared as a special filler episode for episode 336. It features Franky as a giant robot called  Gigantic Robot Frangashan　（巨大ロボ　フランガシャーン, Kyodai Robo Furagashān）, who origin ally was not part of the Chopper Man cast. Frangashan is also a robot Usodabada builds, and it is used to fight Luffy Bomber, but is easily defeated. Also, there were a few cameos in this episode, such as Johnny, Yosaku, and Tashigi, who made an appearance in Zorogilla's show. The episode is an original story and continues on where Oda's short left off.

Trivia

 * The short is referenced in the Ending sequence with the song "Adventure World", wherein Chopper adorns his Chopper Cape, and flies around, eventually off-screen. The story was also made into a One Piece television short, which aired at the end of episode 279.
 * Zorogilla has the same belt as Jigorou.
 * Chopper Man makes a cameo in episode 369. For 2 seconds, Chopper is seen wearing the Chopper Man cape (and with a noticeable chibi aspect) after Oars calls himself the "Oars bomber" (a play on the Luffy Bomber) when he believed he was a robot.
 * A poster of "Rivals and Villains" by Weekly Shonen Jump artist Yusuke Murata has Chopperman watching over many of the characters within the massive collage from the 40 year history of the manga magazine.
 * In the 4th Japanese fan poll, Chopper Man was voted the 83rd most popular character in One Piece.