M4X-337
From The Stargate Omnipedia
A barren planet in the Pegasus Galaxy, explored by the Atlantis expedition. Baited by a naquadah generator, Dr. Rodney McKay sent the shadow creature through the Stargate to this planet.
DETAILS
HOME TO - shadow creature
FIRST APPEARED - Hide and Seek
KEY EPISODE
Hide and Seek - Peter Grodin suggests the expedition send the shadow creature to this world, ridding the threat from Atlantis.