Well, if they're hanging upside-down from the ceiling, perhaps a spider climb Su is more appropriate. I think they should stay grounded, though.
Any bi-nou clan will have 2-8 eggs, each valued at 100-1,000 gp. The eggs are hard and facted like gems, and are prized by dwarves, who have come to recongnize their value and rarity.
Bi-nou prefer damp, drafty caverns, where it is easier to sense their prey. Such a cavern is likely to hold remnants of weapons and armor, as the bi-nou consume humans and other beings and animals by absorbing the fleshy parts. The rock creatures don’t value these discarded “unlife things”, though they have learned that other living beings—especially humans and demihumans—are attracted to the objects. Bi-nou have been known to use their stone shape ability to put the metallic leftovers on rocky pedestals to attract the attention of passing adventurers.
A bi-nou’s treasure consists of unfortunate adventurers’ gear and the rock creatures’ eggs. Most equipment is worthless, damaged when the rock creatures absorb their prey. However, magical equipment tends to stay in reasonable shape. Bi-nou corpses are used by certain dwarven builders, especially duergar, as solid stone building materials.