  A superhalogen $\rm{F@C_{20}(CN)_{20}}$ and a corresponding Br{\o}nsted
superacid were designed and investigated on DFT and DLPNO-CCSD(T) levels of
theory. Calculated compounds have outstanding electron affinity and
deprotonation energy, respectively. We consider superacid
$\rm{H[F@C_{20}(CN)_{20}]}$ to be able to protonate molecular nitrogen. The
stability of these structures is discussed, while some of the previous
predictions concerning Br{\o}nsted superacids of record strength are doubted.
