If the petrification goes down 3cm into the skin but is hard enough to prevent you from moving, wouldn’t people suffocate? This one seems less magical/unexplainable and more biological, so I doubt its petrification somehow preserves the victim to stay alive.
The fact that it clones itself to reproduce is also probably a really bad idea, as that leaves itself open to being completely wiped out by disease, predators, and loss of habitat. Maybe the Foundation keeps them not out of an attempt to contain, but in order to protect them?