Fight Club Soap is a bar of soap that was created using the original props from Fight Club:

“Plenty of soaps are made with natural ingredients. Usually what that means is that they’re made of ground-up flowers and tropical fruits.
If you’re going to shower, be a man about it. Introducing the only soap made with electrolytes, caffeine, and punching. Don’t waste your time with anything less.
You’re welcome.”

[via Laughing Squid]