Tentacle Rod

From Dungeon Master's Guide, page 208. Found on Magic Item Table G.

Description
Rod, rare (requires attunement).

Made by the drow, this rod is a magic weapon that ends in three rubbery tentacles. While holding the rod, you can use an action to direct each tentacle to attack a creature you can see within 15 feet of you. Each tentacle makes a melee attack roll with a +9 bonus. On a hit, the tentacle deals 1d6 bludgeoning damage. If you hit a target with all three tentacles, it must make a DC 15 Constitution saving throw. On a failure, the creature's speed is halved, it has disadvantage on Dexterity saving throws, and it can't use reactions for 1 minute. Moreover, on each of its turns, it can take either an action or a bonus action, but not both. At the end of each of its turns, it can repeat the saving throw, ending the effect on itself on a success.