  In this work, we explore the intriguing possibility of connecting
self-interacting dark matter (SIDM) with the recently observed exceptionally
bright and long-duration Gamma Ray Burst (GRB221009A). The proposed minimal
scenario involves a light scalar mediator, simultaneously enabling dark matter
(DM) self-interaction and explaining the observed very high energy (VHE)
photons from GRB221009A reported by LHAASO's data. The scalar's mixing with the
standard model (SM) Higgs boson allows for its production at the GRB site,
which will then propagate escaping attenuation by the extra-galactic background
light (EBL). These scalars, if highly boosted, have the potential to explain
LHAASO's data. Moreover, the same mixing also facilitates DM-nucleon or
DM-electron scatterings at terrestrial detectors, linking SIDM phenomenology to
the GRB221009A events. This manuscript presents the parameter space meeting all
constraints and offers an exciting opportunity to explore SIDM in future direct
search experiments using insights from the GRB observation.
