Barzan wormhole

The Barzan wormhole was a wormhole which had one terminus near the Barzan homeworld and another that was unstable and shifted between the Gamma and Delta Quadrants.

The Cardassians knew or suspected the existence of the wormhole more than a decade before its discovery. Elim Garak studied it while he was at the Bamarren Institute for State Intelligence. 

In 2366, the Barzan people began taking bids on who would get to own the wormhole, although the negotiations collapsed when it was discovered the other terminus of the wormhole unstable and worthless for use. Two Ferengi were lost when they were unable to return to the Alpha Quadrant. 

In 2373, the two Ferengi were found by the USS Voyager and tried to escape back through the wormhole. They made both ends of the wormhole unstable in their attempt.