1. The famous carbonated drink that only 5 people know the exact base to.
2. Any drink in which hot sauce has been put in as a prank. Generally, hot sauces of 600,000 Scoville or greater are used to minimize the amount needed, and thus minimize the chance of detection before it's too late.
A: He really embarrassed you with that picture of you passed out naked.
B: It's ok, I think I got him back.
B: I gave him a "Dr. Pepper".
A: Made with what?
B: His favorite, Rum and Coke, with a bit of concentrated Capsaiccin solution added in.
A: You realize that might kill him?
B: Nah, I only put a tiny droplet of the solution in, but he definitely won't be having fun tonight.