Rime Scroll

Scroll, rare

When you cast a spell that deals cold damage, as a bonus action you can read the rime scroll as part of the act of spellcasting. You must have a free hand to hold the scroll.

Creatures taking at least 10 cold damage from your spell are sheathed in clinging frost, impeding their movements.

Their speed is reduced by half and they have disadvantage on Dexterity checks and saving throws. A creature can attempt a Strength saving throw each round at the end of their turn to break free from the ice. The DC is equal to 8 + the level of the spell you cast when using the rime scroll.

The save DC decreases by 2 every round after the first. A creature also is freed immediately if they take at least 10 fire damage Incorporeal or gaseous creatures, creatures already made of snow or ice, and Huge or larger creatures are immune to this effect, as are creatures using freedom of movement. Dispel magic can destroy all ice created by a rime scroll. A rime scroll can be used only once.