As two actions, a creature that is made of flesh that you can touch or see within 10 meters must make a Fortitude saving throw.
On a failure, its body starts to turn into stone as it is slowed 2.
On a success, the slowed level is reduced by 1.
On a failure, the slowed level increases by 1. The spell ends if the slowed level is reduced to 0. If the slowed level reaches 4, the creature is turned to stone, no longer makes saving throws each turn, and is subjected to the petrified condition for the duration.
If the creature is physically broken while petrified, it suffers from similar deformities if it reverts to its original state.
If you maintain your concentration on this spell for the entire possible duration, the creature is turned to stone until the effect is removed.