Arpazo

Human-skin Sack. Any creature that enters the Arpazo's sack is transported to a demiplane that can be entered by no other means except a wish spell or the Arpazo's Stuff Inside ability. A creature can leave the demiplane when the Arpazo wills it, or by magic that enables planar travel, such as the plane shift spell. The demiplane resembles the inside of a burlap sack roughly 1,000 feet in diameter with a ceiling 1,000 feet high. The human-skin sack cannot be damage from the inside. If the Arpazo dies, its sack turns to ash, and all creatures inside reappear in an unoccupied space within 10 feet of the sack. The demiplane is otherwise indestructible.

Innate Spellcasting. The Arpazo's innate spellcasting ability is Intelligence (spell save DC 14, +6 to hit with spell attacks). It can innately cast the following spells, requiring no material components:
At will: burning hands, charm person, detect magic, dispel magic 
3/day each: misty step, wall of fire
1/day: plane shift (transports the Arpazo and any creatures within the human-skin sack)

Magic Resistance. The Arpazo has advantage on saving throws against spells and other magical effects.

Magic Weapons. The Arpazo's weapon attacks are magical.

Teleport. As a bonus action, the Arpazo magically teleports, along with any equipment it is wearing or carrying, including creatures within the human-skin sack, up to 60 feet to an unoccupied space that it can see.   

Multiattack. The Arpazo makes three scimitar attacks.

Scimitar. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage plus 3 (1d6) fire damage. 

Stuff Inside. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: if the creature is size Medium or smaller, it is magically teleported to an unoccupied space on the floor inside of the Arpazo's human-skin sack, and remains there until the Arpazo wills their exit, or the Arpazo dies.