Hornworms
https://giantveggiegardener.com/category/organic-pest-controls/uv-light-for-tomato-hornworms/
They light right up!
Yes, I bought a fairly powerful UV flashlight, mainly for that very purpose. It works well on a really dark night, but, night B4 last was not that dark when I went out to the garden. (Moonlight). I hunted again that morning but only found one hornworm. The others were better hidden, it would seem. :-(