Tentacle Staff

Staff, very rare (requires attunement by a sorcerer, warlock, or wizard)

This staff can be wielded as a magic quarterstaff that grants a +2 bonus to attack and damage rolls made with it. On a successful melee attack, the wielder may use a bonus action to cause the target to become grappled (escape DC equal to your spell save DC). This staff has 10 charges and regains 1d6+4 expended charges daily if submerged in water.

If you expend the last charge, roll a d20. On a 1, the staff dissolves into a translucent slime.

Spells. While holding the staff, you can use an action to expend some of its charges to cast one of the following spells from it, using your spell save DC: acid splash (1 charge), black tentacles (4 charges), enthrall (2 charges), major image (3 charges) Transformation. As an action, you may spend 5 charges to force a creature grappled by the staff to make a Constitution save against your spell save DC or become diseased. The disease has no effect for 1 minute. After 1 minute, the diseased creature’s skin becomes translucent and slimy and the creature can’t regain hit points unless it is underwater. When the creature is outside a body of water, it takes 6 (1d12) acid damage at the end of every 10 minutes unless moisture is applied to the skin.