GELF

GELFs (genetically engineered life forms) are creatures developed by humanity for varying purposes. When humanity died out many GELFS began to develop personalities of their own and populated the otherwise empty universe.

Humanoid
Humanoid GELFS are, as the name implies, genetically engineered life forms which have a similar build to Humans. Such species were often bred as quartermasters on ships and later formed primitive tribes in some parts of the universe.

Pleasure
Pleasure GELFs are a friendly species of GELF with telepathic capablities. They can read the minds of others, determine what is the perfect partner for them, and then take on the appearance of such a character, sometimes taking several different forms at once. For instance, when the crew of the startship Red Dwarf met a pleasure GELF it took on the form of a feminine android when speaking to Kryten, for Rimmer it appeared as a female hologram with similar tastes to him, and for Cat it was an identical copy of himself.

Polymorph
Polymorphs are bizarre shape-shifting creatures originally designed as a weapon. They can change into anything, allowing them to perfectly blend into the background. When it attacks people, it drains of them of their negative emotions.

Psiren
Much like pleasure GELFs, psirens can telepathically read the minds of other life-forms and create illusions which appeal to them. However, psirens use this capability as a weapon with which to lure others into a false sense of security, typically to trick passing ships into crashing into asteroids so tht they can suck out the brains of the crew.