Tyrant's Whip 2014
Weapon, uncommon
This wicked whip has 3 charges and regains all expended charges daily at dawn. When you hit with an attack using this magic whip, you can use a bonus action to expend 1 of its charges to cast the command spell (save DC 13) from it on the creature you hit. If the attack is a critical hit, the target has disadvantage on the saving throw.
Properties
Reach
This weapon adds 5 feet to your reach when you attack with it, as well as when determining your reach for opportunity attacks with it.
Source: Vault of Magic (Kobold Press) · License: OPEN GAME LICENSE Version 1.0a details