"Well, he's been attacking the aliens with his death ray."
"It's a shame we don't have one."
- - Tom Paris and Tuvok (VOY: "Bride of Chaotica!")
Doctor Chaotica's minions fire the death ray
"Death ray" was a term popularized on Earth that described the sort of weaponry possessed by potentially hostile aliens from other planets.
When Quark was stuck on 20th century Earth, he threatened to harm Nurse Garland with his death ray. However, as Lieutenant General Denning observed, "It looks like a finger to me." (DS9: "Little Green Men")
In Tom Paris' The Adventures of Captain Proton holo-programs, Doctor Chaotica had a death ray in his Fortress of Doom. In an accidental conflict between the holodeck characters and photonic lifeforms in 2375, the death ray in fact killed over fifty of the photonic aliens. (VOY: "Bride of Chaotica!")