As Wikipedia says, paedomorphism is the retention by adults of traits previously seen only in juveniles.

Page 318, line 22 of The Ancestor’s Tale by Richard Dawkins. The section is about axolotls, a type of amphibian which becomes sexually mature while they still have their juvenile characteristics (gills, especially).

I like the idea of a cop who pretends to be a kid to bait paedophiles. I also liked how you described his inner thoughts. Gave it all an extra feeling.

Seems familiar somehow though, I think I’ve watched something like this in a video :)