Frostglow Rapier

These mithral weapons are commonly found among gnomes and quicksteps, who prize their power to shed a chilling blue light on command. You can use a bonus action to speak this weapon's command word, and all creatures within 30 feet must succeed on a DC 15 Constitution saving throw, becoming paralyzed for 1 round on a failed saving throw and having their speed reduced to zero for 1 round on a successful one. The effect ends at the beginning of your next turn. This action cannot be used again until the next dawn.

Finesse: When making an attack with a finesse weapon, you use your choice of your Strength or Dexterity modifier for the attack and damage rolls. You must use the same modifier for both rolls.

Proficiency: martial, rapier Source: Book of Ebon Tides p. 209 (Third Party), Player's Handbook (2014) p. 149