Tesla's death ray
Sci-Fi
Tesla's death ray

What Exactly Defines a "Death Ray"?

The Death Ray

The quintessential "death ray" exists in fiction, and in visual media it is often represented as a futuristic ray gun that shoots a beam. So the major components are the "death" element, and the "ray" element. Both of these need to be present in some form for it to be considered a death ray.
The Righteous Bison from Team Fortress 2

Atomic Style

Like many science fiction tropes, the death ray can often be linked to feelings about the atomic bomb and nuclear power as a whole. It is a weapon of untold power and destruction, the likes of which can be wielded by a single man.
That's no moon...

Titular Evil

Some stories feature death rays as the main source of conflict. In Star Wars, a moon-sized planetary death ray drives the climax of the film.
Set death ray to

Is This a Death Ray?

On paper, an x-ray machine is totally a death ray. It is a beam/ray, it's futuristic and linked to radiation, and it can kill you. Granted, it takes a little while to actually kill you, generally due to radiation poisoning or cancer. When x-rays were first invented, people were unaware of the danger, and the machine was used for recreational activities as well as medical ones.
Optic blast!

Cyclops

Cyclops from the X-Men comics shoots an uncontrollable beam from his eyes. These blasts are concussive force, likened to a "punch dimension". I do not consider Cyclops' powers a "death ray".
A living death ray.

Atomic Breath

Godzilla's signature atomic breath is most definitely a death ray. "Godzilla" is one of the most well-known allegorical characters and movies regarding the atomic bomb.
A snapping shrimp, family Alpheidae

Pistol Shrimp

Pistol shrimps are a very real animal with a "death ray" of sorts. The large claw can snap shut with such force, it produces a "bullet" which travels 100k/h and kills small fish.