The Bene Tleilax - commonly called the Tleilaxu - are a secretive and widely distrusted civilisation of genetic manipulators. Their most notable creations are gholas (cloned bodies grown from the cells of the dead, capable of having their original memories restored) and Face Dancers (shapeshifters who can perfectly mimic other people). The Tleilaxu's technology is biological rather than mechanical, skirting the prohibitions of the Butlerian Jihad, and their motives are opaque to outsiders. They play an increasingly important role across the Dune saga — providing Duncan Idaho gholas, conspiring against Paul in Dune Messiah, and becoming central to the power struggles of Heretics and Chapterhouse. Their true nature and the religious beliefs that drive them are among the later novels' most significant revelations.