  Some time ago it was suggested that dark matter may consist in part of an
extremely dilute gas of supermassive gravitinos with fractional charge 2$e$/3
\cite{MeissnerNicolai2019}. This scheme makes the definite (and falsifiable)
prediction that massive gravitinos are the {\em only} new fermionic degrees of
freedom beyond the known three generations of quarks and leptons of the
Standard Model of Particle Physics. In this note we re-examine one special
outlier event reported and subsequently discarded by the MACRO collaboration
\cite{MACRO1} in the light of this proposal and point out the possibility of an
alternative interpretation of this event supporting the above hypothesis, whose
confirmation (or refutation) would, however, require an independent dedicated
experimental effort.
