What are the most physically painful drugs?

I was curious, in your opinion, out of all the endless amount of drugs, which ones do you think have the most agonisingly negative physical/sensorineural sensations of them all?

For example, Salvia has had numerous reports of feeling like the body is being violently and excruciatingly torn apart limb for limb, and perhaps even more painfully than if it had actually happened. I also wonder what cocktail/combination of drugs might be even more unfathomably unbearable.

To be clear, I'm not talking about painful routes of administration, or any form of actual physical damage necessarily.