Protouniverse
From Memory Alpha, the free Star Trek reference.
In 2370 Jadzia Dax and her Trill initiate Arjin snagged a protouniverse in the USS Mekong's starboard nacelle when it accidentally collided with a subspace interphase pocket in the Gamma Quadrant. While studying the protouniverse back on Deep Space 9 Jadzia noted that it contained high plasma concentrations and a rapidly expanding mass. She also noted that it had properties that did not conform to our rules of nature and showed indications of life.
The protouniverse was eventually taken back through the wormhole (and supposedly back into the subspace pocket) in order to keep it from displacing our own universe. (DS9: "Playing God")
