Bagman

Bag of Holding. The Bagman emerges from a Bag of Holding, which it can enter and exit as a bonus action.

Keen Smell. The bagman has advantage on Wisdom (Perception) checks that rely on smell.

Regeneration. The bagman regains 10 hit points at the start of its turn. If the bagman takes radiant damage, this trait doesn't function at the start of the bagman's next turn. The bagman dies only if it starts its turn with 0 hit points and doesn't regenerate.

Grappler. The Bagman has advantage on attack rolls against any creature grappled by it.

Amorphous. The Bagman can move through a space as narrow as 1 inch wide without squeezing.

Alien Mind. If a creature tries to read the Bagman's thoughts, that creature must succeed on a Intelligence saving throw DC 17 or be stunned for 1 minute. The stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Terrifying Presence. When the Bagman enters the battlefield, all creatures within 30 feet of it must make a DC 14 Wisdom saving throw, or become frightened for 1 minute falling prone in fear. A creature can repeat this saving throw at the end of each of its turns, ending the effect on a success.

Frightening Appearance. The Bagman is an unnerving sight, with tendrils that writhe and twitch. Any creature that sees the Bagman must make a DC 14 Wisdom saving throw, or take 1d4 psychic damage and be frightened of the Bagman for 1 minute falling prone in fear. A creature can repeat this saving throw at the end of each of its turns, ending the effect on a success.

Extradimensional Horror. Anytime The Bagman grapples a creature while still in its bag, that creature must pass a DC 18 Strength check. On a failed check, The Bagman pulls that creature inside its bag. A creature inside a bag can use its action to try to escape with a successful DC 18 Strength check. Another creature can use its action to reach into the bag to pull a creature out, doing so with a successful DC 20 Strength check. Any breathing creatures that have spent more than a number of minutes equal to 10 divided by the number of creatures (minimum 1 minute), begin to suffocate. 

Multiattack. The Bagman makes one bite attack and two tendrils attacks.

Bite. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 7 (1d6 + 4) piercing damage.

Tendrils. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 13 (2d8 + 4) piercing damage.

Consuming Tendrils. The Bagman can makes a melee attack against a creature within 10 feet of it with its tendrils. On a hit, the target takes 2d10+4 piercing damage and the Bagman attempts to drag it into the Bag of Holding. The target must make a DC 14 Strength saving throw, or be dragged into the bag. While inside the bag, the target takes 3d6 acid damage at the start of each of its turns. The Bagman can only have one creature in its bag at a time, and it can choose to release the creature at any time as a bonus action. If the creature is reduced to 0 hit points, it is consumed by the Bagman.

Retract to the Bag. As a reaction, the Bagman can retract itself into the bag of holding if it is within 30 feet.