This cross-stitch, "The Fenwick Special," glows in the dark. Now this is just an idea that's ready-made for abuse. And by abuse I mean the fun kind. Imagine all manner of innocuous, normal, ho-hum cross-stitch bits that, with the lights off, turn into crass declarations of mayhem. Maybe letters drop out, maybe you've cross-stitched white glow-in-the-dark stuff in with regular white, so the hidden message only appears in the dark.
Have a warm, happy "Welcome to Our Home" cross stitch in your guest bedroom that becomes a huge "GET OUT" when the lights are turned off.
I'm telling you: the sky's the limit.