Photon Mutilators was the name the Simulant Generals used to describe their very powerful torpedo missiles. They were fired from their mobile command base, the Simulant Death Ship, and their attack craft, the Annihilators.
These Simulants apparently didn't use laser cannons, instead only using their missiles. The Photon Mutilators could seemingly destroy anything they touched, with Red Dwarf only being saved from their bombardment due to the massive size of the Dwarf, although they still heavily damaged it.
After the thief Hogey the Roguey stole a prized cloth map from the Death Ship whilst the Simulants slumbered, the Death Ship gave chase. Unfortunately, Hogey went strait to Red Dwarf, since he was familiar with the crew and had a strange obsession with the gang, always offering them "duels across time and space". Hogey had apparently stolen the map to use as leverage in his games. However all he succeeded in doing was bringing the Simulant Death Ship strait to Red Dwarf.
As the Death Ship approached Red Dwarf, Dominator Zlurth ordered the Annihilators to be launched and to begin bombarding the Dwarf with missiles. A hole was made in the hull of the sleeping quarters, which luckily for the Dwarfers was sealed when Hogey fell into it. The Dwarfers then ran down to the nearby cargo bay 3 where a Blue Midget was parked, and they fled into a nearby asteroid belt. Dominator Zlurth ordered his Annihilators to blow up the asteroids one-by-one, eventually forcing the Dwarfers out.
Rimmer was able to come up with a plan after some receiving some startling revelations about his true parentage from his holo-lamp. Blue Midget left the asteroid belt to face the Death Ship and it's attack craft, which took position around Blue Midget and fired their missiles at the same time. However, Lister used Hogey's Molecular Destabilizer to make Blue Midget transparent, and the missiles passed harmlessly through Blue Midget, instead crashing into the Simulant ships on either side, destroying them instead with their own missiles. (The Beginning, Series X)