Dr. Hogback is a world famous doctor, who according to Chopper saved as many people as there are stars in the sky. One day he disappeared from the public eye, causing turmoil in the medical community. Nami, Usopp, and Chopper meet him on Thriller Bark, and he explains to them that he is researching the nature of life and death using the zombies on the island. This is later exposed as a lie when the crew discovers that Hogback himself created the zombies, and is a crew mate of Gecko Moria, who breathes life into Hogback's zombies with the shadows he steals, transferring the fighting ability and personality of the shadow's former owner into the body. He is later seen meeting with Gecko Moria, Perona and Absalom concerning the creation of Zombie #900 and the removal of Luffy's shadow. Hogback faced off against Chopper, who, as a doctor, resents his experiments in zombification for being intended for personal gain rather than the progress of medical science. However, much to Chopper and Robin's dismay, Hogback had prepared Jigoro and Sanji's zombie for the battle to come. After Chopper and Robin being defeated, Hogback and Chopper have a conversation, where Hogback reveals that he never cared about saving lives and the reason he went into hiding was because so many people were coming to him seeking treatment, and that he became a doctor only for the money. Robin outsmarts him by telling him to order Jigoro and Penguin to jump out the window. After facing the betrayal of his beloved zombie version of Cindry, Chopper and Robin prepare to finish him off with a suplex wrestling attack, but the rampage by the massive Oz prevents them from finishing the attack. As Hogback tries to speak with the giant zombie, Oz squishes him under his massive foot. It's shown, however, in chapter 483 that Hogback somehow survived from Oz's attack. Like many other characters in One Piece, Hogback has a unique laugh (fosfosfosfos). Many members of Thriller Bark seem to be based on old Horror movie character types; Hogback seems to be based on mad scientists, in particular Dr. Frankenstein. (Source: Wikipedia)