From Creatures Wikia
Sliders are so named because instead of moving about and eating, playing, and breeding normally, they are stuck indefinitely in a screen-facing position- when led by the Hand, they will only "slide" along the ground.
The specific cause for the mutation is usually unknown, though Creatures of mixed origin, such as the offspring of a Grendel/Norn splice, seem to have a higher number of paralysis cases than normal, along with Creatures of Dream Norn descent. Also the (grand)children of Element Norns are frequently born with this mutation. These occurrences are most likely caused by parents having an unequal amount of pose or gait genes (or both). In the case of crossbreeds of Amanora's genomes and normal creatures, it is due to the pigment genes from Amanora's genomes being in the same location as pose/gait genes in the CL genomes. Some have speculated that moving an egg too much or neglecting a pregnant Creature's needs may also play a factor.
The prognosis for sliders is bleak. Because they are not capable of eating or otherwise taking care of their needs, many die before reaching adolescence. Although it is possible to force age sliders, inject them with the chemicals they need to survive, and in rare cases, breed them, most players choose to export or euthanize their sliders to avoid unnecessary suffering or having to deal with them.
If the missing or mutated genes are corrected, a clone of the affected Creature is capable of living normally; however, there is no known way to "fix" the original.
The Slider Syndrome is an inheritable mutation.