I think the misunderstanding might come from the fact that a Magnetar produces many gamma ray bursts over thousands of years until it finally runs out of energy

I think the misunderstanding might come from the fact that a Magnetar produces many gamma ray bursts over thousands of years until it finally runs out of energy, but a supernova is a completely different process which happens only once per star. > So, what is it about this event that makes it unique (i.e. produce ultra-long GRB). In the case of supernovae, I believe the current model for producing UL-GRBs is that it has to be a massive star collapsing into a black hole, possibly followed by a relatively prolonged period of intense feeding on the star's remnants. By contrast, a Magnetar discharging some of its built-up electromagnetic energy in our direction, could potentially be the more likely cause of any given long-lasting GRB. > 1) This was a star going nova, producing a Magnetar with a particularly strong magnetic field The GRB caused by a collapsing star would not be different based on whether the end product is a Magnetar or a normal neutron star. > 2) This was a Magnetar whose magnetic field decayed to the point that it caused a massive explosion/release of energy from the object. It's not the decay of the magnetic field that causes this, rather it's a localized build-up caused by the stresses of huge electromagnetic structures pushing and twisting against each other, until suddenly the whole things snaps and unwinds violently (much like a clock that gets wound up very tightly until it breaks).