Bagman

Legendary Resistance (1/Day). If the Bagman fails a saving throw, it can choose to succeed instead.

Alien Mind. If a creature tries to read the Bagman's thoughts, that creature must succeed on a DC 16 Intelligence saving throw 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.

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

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

Keen Senses. The Bagman has advantage on Wisdom (Perception) checks that rely on smell or hearing.

Regeneration. The Bagman regains 20 hit points at the start of its turn. If the Bagman takes necrotic damage, this trait doesn't function at the start of its next turn. The Bagman dies only if it starts its turn with 0 hit points and doesn't regenerate.

Unusual Nature. The Bagman doesn't require air, food, drink, or sleep. 

Multiattack. The Bagman makes five attacks: two with its bite and three with its claws. It may replace one of its claw attacks with a grapple action.

Bite. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 23 (4d8 +5) piercing damage.

Claw. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 15 (3d6 + 5) slashing damage.

If grappling a creature, the Bagman may use the Death Squeeze bonus action on them, along with any main actions it takes.

Death Squeeze. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 17 (6d4 + 2) necrotic damage and 9 (1d8 + 5) bludgeoning damage. Any creature hit by the Death Squeeze must choose whether to use an action or bonus action on its next turn. In addition, the Bagman heals an amount equal to the amount of necrotic damage dealt.

The Bagman can take 2 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Bagman regains spent legendary actions at the start of its turn.

Acidic Claw. The Bagman makes one claw attack, and adds an additional 7 (2d6) acid damage to the damage roll.

Detect. The Bagman makes a Wisdom (Perception) check.

Frightening Gaze (Costs 2 Actions). The Bagman fixes its gaze on one creature it can see within 15 feet of it. The target must succeed on a DC 16 Wisdom saving throw against this or become frightened for 1 minute. The frightened target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to the Bagman's gaze for the next 24 hours.