Caught_by_light creates dramatic images of scenes with light from above or behind. Characters or items that are the focus of the lora may be cast in shadow and seen only in silhouette while a light shines over their shoulder; they may be surrounded by crepuscular rays from above, as a divine being or alien visitor reaches out to them; a ray of sunshine through a blind could highlight a sleeping form.
It works best with prompts in the form of "Caught_by_light your character or object in the darkness".
Leaving off "in the darkness" will still get crepuscular rays or backlighting, but they'll be less of a feature as the generated image will be brighter overall.
Long prompts should come after both, to avoid the effect getting lost.
A strength of 1 is usually sufficient; 1.5 works as well. 2 can work, but will sometimes throw up some degraded graphical effects.