[Action]
[he takes Zelgadis's hand lightly, sliding fingers over it measuringly. musing to himself] It really is stone.
My sister Raven has skin that looks rather like this -- blue, and textured. But it is flesh, at least.
It seems likely that the injection wouldn't be able to pierce your stone skin. We'd have to find another delivery method, if the serum is completed in the future.