The subject of this effect cannot take any actions or reactions, they cannot move. Any attacks against the subject are made with advantage. Attacks against the subject have advantage, but the subject takes half damage.
If the subject has the Poisoned, Invigorated, Ailing or similar status effects when they are petrified, they will continue to have that effect when the petrified effects ends, with the same amount of duration which was remaining when they became petrified.