Encase in Metal

You encase yourself or another creature in metal plating, either as armor or imprisonment. You or another Medium or smaller sized creature within range must make a Dexterity saving throw or become encased. A target can choose to fail the save if they are willing.

Armor. The target's AC becomes 13 + its Dexterity modifier, unless its AC is already higher. The armor remains until it is removed with magic.

Imprisonment. The target is restrained by the metal and its AC becomes 15. The target can use its action to make DC 20 Strength check to break the armor, freeing itself on a success.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, you can target a creature one size category larger for each level higher than 3rd.