Antimatter torpedo

From Memory Alpha, the free Star Trek reference

An antimatter torpedo was a type of weapon used by the Kovaalans in 2154. The yield of the torpedo could be varied, much like that of a photon torpedo. (ENT: "E²")

The inhabitants of Kelemane's planet developed antimatter torpedoes to be used against the USS Voyager, which they knew as the Sky Ship. (VOY: "Blink of an Eye")