A badly designed reling, usually existing only for a short time before they are destroyed by the physical limitations of rl.
Some relmosters are actually monsters. Creatures from the cheap entertainment virches, including erotic, game and thriller virches, which cause havoc and destruction in the rl, before being destroyed by angelnet, rl inhabitants or laws of reality.
Production of dangerous relmonsters is illegal and punished by erasing the virtual existences who created them. Nevertheless, some still sneak through.