The displacement engine weapon engulfs a Scarran Dreadnought
Two wormhole weapons were seen in the series: The first was the displacement engine which was jury rigged from a phase stabilizer by "Jack" the Ancient and John Crichton. It opened a wormhole on the edge of star, in such a position that one end of the wormhole touched the star's surface and displaced a large quantity of matter from the interior of the star. This matter accelerated through the wormhole, exiting the other end as an enormous bolt of plasma (apparently nearly the size of a small moon) which was propelled into a Scarran Dreadnought, utterly destroying it. It was essentially an extremely large-scale mass driver/plasma weapon utilizing a percentage of the mass of a star as ammunition. ("Infinite Possibilities - Icarus Abides")
The black hole weapon
The second wormhole weapon was unnamed and appeared in the Peacekeeper/Scarran War, designed by John Crichton, and installed on Moya with the aid of Moya's Pilot. It used the energies of an initializing StarBurst to create a small, precisely positioned black hole, which then grew exponentially larger in a geometric progression, doubling in size every few seconds. This wormhole weapon-generated black hole would have continued to grow until it engulfed the entire galaxy, and possibly the entire Universe, if it had not been stopped. John used this weapon to demonstrate to the Scarrans and the Peacekeepers that the war they were fighting would only ensure their mutual destruction, and to show them that the wormhole weapons both sides so eagerly sought would only result in destruction on such a massive scale that neither side had even begun to comprehend; wormhole weapons were a universal threat, a danger to the very fabric of the Universe itself. He in effect held both races and the entire galaxy hostage to make peace and succeeded. (The Peacekeeper Wars)