Energy being of M5S-224

These lifeforms inhabited the planet M5S-224, although they did not originate there. To outsiders, they appeared as a nondescript white fog permeating the air around the planet's Stargate; however, in reality they were intelligent beings that were killed en masse whenever the opening Stargate released its unstable vortex.

When Atlantis 1 and Elizabeth Weir came to the M5S-224 intending to dial Earth, which would endanger even greater numbers of them due to the energy required to dial another galaxy, the lifeforms took preventive action. While the intruders were made to believe that they successfully returned to Earth, their minds were actually trapped in an hallucination constructed from their memories of Earth. One of the lifeforms, who assumed the identity of George S. Hammond, eventually revealed the masquerade and agreed to free them in exchange for them leaving the planet and abandoning the plan to contact Earth.