Arbinaq's Shade Shackles

Ghastly enfeebling shackles charged with abjuration spring forth around a target. Choose a creature you can see within range. The target must succeed on a Strength saving throw or have its speed reduced by half and its Strength score reduced by 1d8 + 1 (minimum Strength score of 10). As an action, the target can make a Strength (Athletics) check against your spell save DC. On a success, the creatures speed is no longer reduced. Otherwise, the reduction to their Strength score lasts for the spells duration.