Ma'chello had been a soldier for many hundreds of years, fighting against the Goa'uld. Two billion of his people died rather than turn him over to the Goa'uld, and he insisted that if it were not for his refusal to surrender, several System Lords would have conquered Earth. He developed advanced technology to battle the Goa'uld, but was eventually betrayed by his wife who had been secretly taken as a host. He was captured and tortured and marked to become a host himself so that his knowledge could be retained, but before the implantation, he killed several Jaffa and escaped. For more than one hundred years, Ma'chello had been a fugitive from the System Lords. One of Teal'c's first assignments as First Prime of Apophis was to hunt him down.
SG-1 encountered Ma'chello as a frail and elderly man, seemingly the only inhabitant of P3W-924. His laboratory contained inventions to fight the Goa'uld, including a personality transfer device that allowed for body switching. With it, he traded bodies with Daniel and took a "holiday" wandering the streets on Earth before being apprehended. He offered his knowledge to save Earth in exchange for keeping Daniel's body, but was finally convinced to relinquish Daniel's body and return to his own, in which he quietly died of pulmonary failure. His many inventions were confiscated by SG-1 for study at Area 51.
Portrayed by: Michael Shanks
Cross Reference: Fred, Ma'chello's Inventions, P3W-924, Personality Transfer Device
Episode Reference: Holiday, Legacy