You trap a creature in a thick coating of ice. The target must succeed on a Dexterity saving throw or be restrained for the duration. At the beginning of each of the trapped creature's turn, it takes 2d4 cold damage. On its turn, an entombed creature (or an ally) can take an action to make a Strength check against your spell save DC. On a success, the entombed creature is freed. The icy tomb is also susceptible to damage and vulnerable to fire. Damage equal to your spell save DC will destroy the tomb and free the target.