A Superluminous Supernova (SLSN or Superluminous SN or Hypernova) is a stellar explosion more energetic than a normal Supernova, i.e., they can be classified as very large Supernovae. Most are Type Ic or Type IIn supernovae, termed Type I SLSN (or SLSN-I), Type II SLSN (or SLSN-II), They are theorized to be Core Collapse Supernovae, but some don't fit that pattern. They are also thought to be the origin of long-duration Gamma-Ray Bursts (LGRBs).
A third type called SLSN-R (for "radioactive") apparently with Electromagnetic Radiation produced by a radioactive Nickel isotope.
Among theories explaining their mechanisms:
Fast Radio Burst (FRB)
Gamma-Ray Burst (GRB)