Aberrations are from the Hell Pit army list:
"Aberrations are beyond classification, the aborted experiments of crazed Moulders whose ambitions
outweigh their skills. Invariably driven mad by their fate, Aberrations will go to every length they
can to ensure that their miserable lives are drawn to a close as quickly as possible.
Aberrations often plead for death as they throw themselves upon the enemy's blades."
Wielding a nightmarish assortment of snapping mouths and mutated limbs, these unbreakable monstrosities
are roughly equivalent to a chaos spawn, although the fixed movement value makes them slightly more reliable.