  We present a scenario (SupraNova) for the formation of GRBs occurring when a
supramassive neutron star (SMNS) loses so much angular momentum that
centrifugal support against self--gravity becomes impossible, and the star
implodes to a black hole. This may be the baryon--cleanest environment proposed
so far, because the SN explosion in which the SMNS formed swept the medium
surrounding the remnant, and the quickly spinning remnant loses energy through
magnetic dipole radiation at a rate exceeding its Eddington luminosity by some
four orders of magnitude. The implosion is adiabatic because neutrinos have
short mean free paths, and silent, given the prompt collapse of the polar caps.
However, a mass ~ 0.1 M_solar in the equatorial belt can easily reach
centrifugal equilibrium. The mechanism of energy extraction is via the
conversion of the Poynting flux (due to the large--scale magnetic field locked
into the minitorus) into a magnetized relativistic wind. Occasionally this
model will produce quickly decaying, or non--detectable afterglows.
