Your weapon imparts magick that slows down your foe as you strike them.

The first time you hit with a melee weapon attack during this spell's duration, the attack deals an extra 2d8 Arcane damage to the target.

Additionally, if the target is a creature, it must make a Wisdom saving throw, potentially becoming

Slowed

A Slowed creature can repeat the saving throw at the end of each of its turns. On a successful save, the Slow effect ends.

Critical Success (+10). The target is unaffected.
Success. The target's speed is reduced by 4m until the end of its next turn, then this spell ends.
Failure. The target becomes Slowed for the duration of the spell. A creature affected by this spell can repeat the saving throw at the end of each of its turns. On a successful save, the spell ends.
Critical Failure (–10). As failure, except the target cannot make a save to free itself from this spell at the end of its first turn.

At Higher Levels: Increase the damage by 1d8 for each spell level increase.