Pair instability supernova are the highest energy events, culminating in a hypernova.

As fuel runs out in a supermassive star, radiation pressure in the core decreases. Gravitational pressure increases in the core, heating it up and producing higher energy gamma rays, which in turn create positron/electron pairs, which further decreases radiation pressure, until the entire core erupts instantly in a massive antimatter explosion. The resulting high energy gamma rays can destroy things within 60 lightyears of the explosion.