Unnatural Selection (S06E12)

After rescuing SG-1 from hyperspace, the Asgard leader Thor asks SG-1 help fight the replicators that have overrun his homeworld. The replicators, box-like robots that have the ability to think and evolve, consume everything in their path with an instinctive thirst for the knowledge and experience of those they devour. Thor explains that the Asgard lured millions of the creatures to the planet in an attempt to slow their evolution with a time dilator. Instead the replicators used the device to speed up time, allowing them to evolve at an astonishing rate. SG-1 finds the planet paved in a layer of metal replicator bricks miles thick. Five humans confront the team and order Carter to stop tinkering with time dilator. When she refuses, the humans reveal that they are actually replicators that have "merged" with human forms. The replicator-humans, named First, Second, Third, Fourth and Fifth, disarm SG-1 and probe their memory banks, allowing them to see what the team is thinking at all times. Fifth, who seems sympathetic to SG-1, taps into Carter's mind where their communication can't be intercepted and agrees to help the team escape in return for safe passage from the planet. Faced with the risk of unleashing an army of replicator-humans on an unsuspecting galaxy, the team has no choice but to trick Fifth into missing the ship. Carter reconfigures the time dilator and starts it up just as the replicators realize what's happening. Fifth is captured, but the device quickly slows time to a standstill and allows SG-1 to escape. A replicator ship veers toward O'Neill and crew but it is consumed by the force field expanding outward from the time dilator as SG-1 heads for home. (Metro-Goldwyn-Mayer (MGM))