Tamer's Whip

This whip is braided from leather tanned from the hides of a dozen different, dangerous beasts. You gain a +1 bonus to attack and damage rolls made with this magic weapon. When you attack a beast using this weapon, you have advantage on the attack roll.
When you roll a 20 on the attack roll made with this weapon and the target is a beast, the beast must succeed on a DC 15 Wisdom saving throw or become charmed or frightened (your choice) for 1 minute.
If the creature is charmed, it understands and obeys one-word commands, such as “attack,” “approach,” “stay,” or similar. If it is charmed and understands a language, it obeys any command you give it in that language. The charmed or frightened creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.