Slitting open the belly of a cute young girl from tits to clit and making her watch as I tug out all her plumbing. She would be forced to watch me disembowel a pig alive first so she can anticipate what's to come for her. I'd use a heated knife on her and carefully cauterizing along the way so there's minimal bleeding, just messy coils of bowel pulled out the front of her belly as far as they will go and then left hanging between her legs. Done in a clean room, in front of a mirror, temperature controlled. She'd be on antibiotics, on painkillers and stimulants to prevent shock. Maybe she'd last for days or even weeks like this under the right conditions. I wouldn't wait that long though, after a few days I'd begin to slowly peel off all her skin in one giant piece, starting with her head/face and working my way down. She'd still be alive and lucid when finished, just a writhing skinless body, raw muscle and purple veins exposed, belly open and guts extruded. Completely reduced to living, breathing meat, then left to slowly expire.

I have some pretty dark and sick fantasies, but they are just that, fantasy. Normal disclaimer that I'd never do anything like this to someone in real life.