Fantasy-ass collection of facts:
There is an acid that is stronger than any other known, and plausibly than any other possible acid.
It cannot be prepared in bulk or stored, because it immediately reacts with any material container, including those graded for all the weaker acids.
When it's needed, it's made in-place, in individual molecules, through nuclear decay.
It is plausibly the first chemical compound to form in the universe.
Behold:



















