Demon, VOY 4
When Paris and Kim go to the Class Y planet and wear their environmental suits they look like Christmas lights.
The “silver blood” of deuterium-ooze creates replicated people – and thus begins a new, toxin-breathing planet.
Janeway allows doubles of the crew to live in order to get off the planet. Picard wouldn’t swing that way. I don’t think so. Anyway, kinda cool.