Mass

Mass are a non-sentient species of amorphous creatures that are little more than clumps of base organic matter.

History
Washu combined her own DNA with one or more Mass to create her daughter, Ryoko Hakubi. Washu's assistant Yakage also saw potential in clones created from Mass, so he took a partial DNA sample from Ryoko, completed it with copies of his own X chromosomes, and combined the resulting sample with Mass to create Minagi, who became referred to as Ryoko's "half-sister".