Bartolomeus

Spellcasting. Bartolomeus is a 3rd-level spellcaster. Its spellcasting ability is Charisma (spell save DC 14, +4 to hit with spell attacks). 
Cantrips (at will): Firebolt, Campfire
1st level: Sleep (5d8)
3rd level: Counterspell

Multiattack. Bartolomeus can make two brass knuckle attacks each turn or one headbutt attack.

Brass knuckle. Melee Weapon Attack: +5 to hit, reach 5 ft., 1 target. Hit: 11 (2d6 + 4) bludgeoning damage. 

Headbutt. Melee Attack: +6 to hit, reach 5 ft., 1 target. Hit: 14 (3d6 + 3) bludgeoning damage. Target must make a DC 15 Constitution saving throw or be stunned for 2 turns, remake throw at end of turn.

Up and Serve (once per long rest). Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 13 (2d8 + 4) bludgeoning damage.  Bartolomeus throws two punches. If both attacks connect, Bartolomeus throws an uppercut into the target's stomach and then into their chest. The target must make a DC 17 Dexterity saving throw. If the target fails the dexterity save, they get launched into the air by the first hit and 15 ft. away and prone by the second one. If the target collides with an object or creature during those 15 ft., they need to make a DC 14 Constitution saving throw or be stunned for 2 turns with the possibility of a repeated throw at the end of their next turn. 

Shrug off. If Bartolomeus is suffering from a status effect, he can spend a reaction to shrug it off. (Recharge 6)