radiation
An emanation of hazardous electromagnetic energy.
In media, it is often stereotypically depicted as green gas or ooze. A more realistic depiction would be a blue or purple haze/glow around the emitting object, to represent the ionization of the surrounding air and/or Cherenkov radiation caused by extremely radioactive objects or film grain from the exposure of radiation on a camera lens. An artistic representation may be stylized "rays" coming from this object.
