Asters Iced Fortress

You unleash a violent burst of pressurised water from your position. In an instant, the explosion freezes, forming a jagged prison of ice that seals enemies inside. While others are trapped, you are able to slip through the glacial fort.

ALL effected creatures (including allies) must make a CON save:

On a fail: The creature is encased in thick ice and becomes restrained for the duration unless freed or they succeed a strength saving throw, allowing them to move within 5ft around them.

On a success: the creature is pushed away to the edge of the ice prison and is not encased, but is slowed, halving their movement for the spell's duration.

Each 5ft of ice has the following stats:
AC: Your spell save DC
HP: Spell level x 5 (at 4th level this is 20HP)
Immunities: Cold, Poison, Psychic
Resistances: Piercing, Slashing
Vulnerabilities: Fire, Bludgeoning