Billis (bil-is)

Billis, or “billi” (plural), were slug-like invertebrates. They crawled on six legs but had an underbelly layered with mucus to help them adhere to cavern walls. A pair of antennas was the only way to communicate and gauge their surroundings because they had no eyes. Caves in Fabella were absolutely covered with billi. If they were irritated, billi would glow pale blue and provide light in dark places.