Gorgon water

Gorgon Water is a banned substance on all civilised worlds where it is known. It is so named because it causes any who are injected with it to turn to stone.

Fortunately treatment is easy: coconut milk completely reverses the effects, when applied to the skin even in part.

Gorgon water was used temporarily as a weapon, but its methods of creation and possibility for uncontrollable abuse were too great, leading to its ban.