Whip of Zeif

You have a +2 bonus to your attack and damage rolls made with this magic weapon. As a Magic Action, you can crack the whip in the air. Each creature within 120 feet that can hear the crack must succeed on a DC 17 Constitution saving throw or has the Deafened condition for 1 minute. At the end of each of its next turns, an affected creature can make another Constitution saving throw, ending the effect on itself on a success. Once you use this property twice, you can't use it again until you finish a Long Rest.

Slow (Mastery): If you hit a creature with this weapon and deal damage to it, you can reduce its Speed by 10 feet until the start of your next turn. If the creature is hit more than once by weapons that have this property, the Speed reduction doesn't exceed 10 feet.

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

Reach: A Reach weapon adds 5 feet to your reach when you attack with it, as well as when determining your reach for Opportunity Attacks with it.

Proficiency: simple, whip Source: Treasures from Oerth p. 29 (Homebrew)