New Spell: Entomb

6th-level evocation
Casting Time: 1 action
Range: 60 feet
Components: V, S, M (a sapphire worth 100gp, a small iron bar, a pinch of dirt)
Duration: Concentration, up to 1 minute.

You attempt to encase one creature that you can see within range into a block of ice. The creature must make a Constitution saving throw. On a failed save, it is restrained as it becomes encased in ice. On a successful save, the creature isn’t affected.
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 three times, the spell ends. If it fails its saves three times, it becomes encased in ice and is subjected to the petrified condition for the duration. The successes and failures don’t need to be consecutive; keep track of both until the target collects three of a kind.
If the ice is damaged (30 hit points, AC 12, vulnerable to fire), the target is freed from its imprisonment.
If you maintain your concentration on this spell for the entire possible duration, the creature is entombed until the effect is removed.

NOTE: This spell is based off of the 5e Player’s Handbook Spell Flesh to Stone.