Anime: Zenmai Zamurai

200 years ago, Zenmai Zamurai (Zennosuke at that time) was a thief by profession (albeit not a very skilled one). While stealing from a house one night, he fell down a well and died. He was then resurrected by Daifukunokami (The god of Bounty, 大福の神) and a wind-up key (zenmai, ぜんまい) was placed on his head. If the key wound down, Zennosuke would die. The only way the key can be wound is by Zennosuke doing good deeds. In order to achieve this end, he is given the Dango-ken, which is a sword with Japanese Dumplings skewered onto it. Whenever Zenmai Zamurai sees people doing injustice or generally being out of control, he uses his sword to shoot the dumplings into their mouths. When the dumplings are eaten, the people suddenly become happy and realize the error of their ways.

Source: Wikipedia