Fulminar

Flyby. The fulminar doesn't provoke an opportunity attack when it flies out of an enemy's reach.

Essence of Lightning. Bolts of lightning course around the fulminar's body, shedding bright light in a 5- to 20-foot radius and dim light for an additional number of feet equal to the chosen radius. The fulminar can alter the radius as a bonus action.

Lightning Form. The fulminar can enter a hostile creature's space and stop there. It can move through a space as narrow as 1 inch wide without squeezing. A creature that touches the fulminar or hits it with a melee attack while within 5 feet of it takes 7 (2d6) lightning damage.

Multiattack. The fulminar makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) piercing damage and 7 (2d6) lightning damage and the target can't take reactions until the end of the fulminar's next turn.

Claw. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) slashing damage and 7 (2d6) lightning damage.

Lightning Shackles (Recharge 5-6). The fulminar magically creates three sets of shackles of lightning, each of which can strike a creature the fulminar can see within 60 feet of it. A target must make a DC 16 Dexterity saving throw. On a failure, the target takes 18 (4d8) lightning damage and is restrained for 1 minute. On a success, the target takes half the damage but isn't restrained. A restrained creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.