Headless Ghost (2007)

Original title: คนหิ้วหัว

Ah-Tia, a former sailor, is desperate for money. He reluctantly teams up with a group of thieves to rob a pawnshop to gain money for his daughter's school tuition, but the thieves betray him and brutally murder him by decapitation. Fortunately, Noom, a young and cunning thief discovers his head; it's still fresh, alive, even talking. Meanwhile, his still-moving-body is discovered by Sao, a female officer from the coroner's office. Noom and Sao are forced to team up with both his talkative head and his direction-less body, and help Ah-Tia to try and fulfill his dying wish and help his daughter.