Arrow of Many Worlds

magic ammunition. 

The tips of these arrows are magically covered in small portions of Well of Many Worlds pg213 DMG.

Attack: On impact  a portal opens briefly covering the target in an envelope then closing in the blink of an eye. The target may make a dexterity saving throw of DC18.  On a fail the target disappears to a random plane of existence. On a success the portal fails to envelop the target.

Critical fail if the attacker rolls a 1 on the attack roll the dimensional arrow hits the ground next to the target and the most resent victim comes back from the plane they were sent.  

Notes: Bonus: Magic, Damage, Banishment