Tamer's Whip

A whip of braided leather tanned from a dozen different, dangerous beasts.
When you attack a beast using this weapon, you
have advantage on the attack roll. Once per day,
target beast must succeed on a DC 15 WIS save
or become charmed or frightened (your choice)
for 1 minute. If charmed, it obeys one-word
commands such as attack, approach, stay, etc.
The creature can repeat the saving throw at the
end of each of its turns, ending the effect on a
success.