Tal'vak acid

Ba'al holding a container of Tal'vak acid.

"Don't."

―Jack O'Neill in response to the pain caused by the substance

Tal'vak acid is an acidic substance used by the Goa'uld, notably Ba'al, as a form of torture. When put into contact with flesh, Tal'vak acid slowly burns all of the way through the body of the individual. Though it cauterizes the flesh as it burns, it still causes the subject great pain. A very small amount often finds its way into the blood and begins to spread throughout the body.

A substance that neutralizes the acid and numbs the pains also exists. (SG1: "Abyss")

Ba'al about to release a drop.