Holiday

S2, E17: When the SG-1 team stumble upon the chamber of former Goa'uld enemy Ma'chello they fall victim to his powerful body swapping invention. Ma'chello takes on Daniel's body and the young archeologist finds himself trapped in the body of an old and dying man. In Daniel's body Ma'chello flees the SGC and gets a taste of life on Earth for the first time while Daniel lies on his death bed in the hospital. In an attempt to help their friend O'Neill and Teal'c bring the invention to the SGC but accidentally trigger it and find themselves in each other's body. When Ma'chello is tracked down and returned to the SGC he reveals that the machine's process is irreversible.