Plamenochmat

Weapon (whip), very rare (requires attunement)

You gain a +2 bonus to attack and damage rolls made with this magic weapon, which deals an additional 1d4 fire damage. When you roll a 20 on an attack roll made with this weapon, the target is restrained. At the start of each of its turns, the target must make a DC 15 Strength saving throw. It takes 2d6 fire damage on a failure, or half as much damage on a success. A creature that succeeds on its saving throw is also no longer restrained. If you move further than 10 feet away from the target, or attack another creature with the flamesnare whip, the restrained condition ends.