Arterial Rime

Select a creature which has blood or is composed of liquid matter. They must make a Constitution saving throw. On fail, they are considered Petrified as the liquids within their body are frozen solid, as well as gaining a vulnerability to fire and bludgeoning damage. Additionally, while the creature is in this state and the caster is adjacent to them, the caster may use a bonus action to sap their strength through the gelid conduit, gaining advantage on attack rolls, ability checks and saving throws.