- You may be looking for LSD.
Acid is a water-soluble compound with a pH of less than 7. It's an ion or molecule that can give up a proton to a base, or accept an unshared pair of electrons from such a base.In a reaction with an alkalis, The two compounds will create water and a salt. This salt is different with different combinations of acid and alkalis.
Dr. Sevrin commited suicide by eating acid-laced fruit. (TOS: "The Way to Eden").
a Horta acid tunnel
The Horta could tunnel through rock by producing an acid. (TOS: "The Devil in the Dark")
Leonard McCoy and his mirror self both caused the same spilling of acid on tables in their respective sickbays, creating a duplicate burn mark on each of them. (TOS:"Mirror, Mirror")