Alu Alilel's Rimestrike

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell's range, otherwise the spell fails.

On a hit, reduce the speed of the target by 10ft until the end of it's next turn. A thin layer of ice spreads across it. If the target takes the attack action or attempts to cast a spell before the start of your next turn, they also take 1d6 cold damage as the ice shatters.

This spell's damage increases when you reach higher levels.

At 5th level, the melee attack deals an extra 1d4 cold damage to the target, and the damage the target takes for attacking or casting a spell increases to 2d6. These damage rolls increase by 1d4 and 1d6 at respectively 11th level and 17th level.