Treeform (Tree of Decay)

You attempt to turn one creature that you can see within range into a tree. The targeted creature must make a Constitution saving throw. On a failed save, it is restrained as its body contorts into a tree. The size and species of the tree reflects the age and personality of the target. On a successful save, the creature isn't affected. The spell has no effect on constructs or undead. 

A creature restrained by this spell must make another Constitution saving throw at the end of each of its turns. If it successfully saves against this spell two times, the spell ends. If it fails its saves three times, it is turned into a tree and subjected to the petrified condition for the duration. The creature remains aware of its surroundings while petrified, does not have resistance to fire damage, and is not immune to poison or disease. 

If you maintain your concentration on this spell for the entire possible duration, the creature is turned to a tree until the effect is removed. Each time you cast this spell you must make a DC 10 Constitution saving throw. On a failed save, a part of your own body begins to petrify into wood. Petrification begins at the end of the limb used to cast the spell and continues upward. If a single limb suffers this effect 3 times it loses all functionality. This effect cannot be removed by any magical means short of a Wish spell.