Gravimetric torpedo
From Memory Alpha, the free Star Trek reference
A gravimetric torpedo was a type of projectile weapon.
In theory, if a gravimetric torpedo was used to detonate a type-6 protostar, it could result in the formation of a wormhole.
In 2374, when the Omega Directive came into effect on the USS Voyager, the crew built a 80-isoton gravimetric torpedo by installing a gravimetric charge into a photon torpedo casing. The torpedo was used to detonate the harmonic resonance chamber, thereby eliminating the last remaining Omega molecules. (VOY: "The Omega Directive")
