Allurer

Allure. All creatures in a 150-foot sphere must make a DC 15 Constitution Saving Throw or be charmed by the Allurer. Charmed creatures must spend their turn approaching the Allurer by the quickest means possible. For every turn spent with a 20-foot radius of the Allurer, charmed creatures take 4d8 radiant damage. Charmed creatures can repeat the saving throw at the end of their turns. On a successful save, the effect ends.

Freedom of Movement. The Allurer ignores difficult terrain, and magical effects can't reduce its speed or cause it to be restrained. It can spend 5 feet of movement to escape from nonmagical restraints or being grappled.

Spellcasting. The Allurer is a 5th-level spellcaster. Its spellcasting ability is [Charisma] (spell save DC 18, +5 to hit with spell attacks). The Allurer has the  following spells prepared:
Cantrips (at will): thunderwave
1st level (5 slots):  magic missile, charm person, command, guiding bolt

2nd level (3 slots): magic missile, charm person, command, guiding bolt, suggestion

3rd level (3 slots):  magic missile, charm person, command, guiding bolt

4th level (3 slots):  magic missile, charm person, command, guiding bolt

5th level (3 slots):  magic missile, charm person, command, guiding bolt

Multiattack. The Allurer can use Allure, then makes one tentacle attack and claw attack.

Claw. Melee Weapon Attack: +7 to hit, reach 20 ft., one target. Hit: 22 slashing damage + 2 psychic damage.

Tentacle. Melee Weapon Attack: +7 to hit; reach 30 ft, two targets. Hit: 35 bludgeoning damage + 5 psychic damage. If two creatures are targeted, they must be between 10 ft of each other.

Tail. Melee Weapon Attack: +9 to hit, reach 45 ft, one target. The target takes 47 bludgeoning damage and is knocked prone.

Lightcore Beam (Recharge 6).  Ranged Weapon Attack:  +15 to hit,  reach 150 ft, one target. The target takes 78 radiant damage + 28 psychic damage on a failed DC 25 Dexterity save or half as much on a successful save. The ground in a 100 ft radius around the Allurer becomes difficult terrain for 10 turns.

Psychic Scream. The Allurer targets any creatures it can see and unleashes psychic power in a huge burst. All targeted creatures must make a DC 18 Constitution saving throw or take 58 psychic damage and go into Madness for 5 minutes.

The allurer can take 3 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 allurer regains spent legendary actions at the start of its turn.

Magic Missile. The allurer makes a level 5 magic missile attack on one target.

Tail Swipe. (Costs 2 Actions). The allurer makes a tail attack.

Legendary Resistance (Costs 2 Actions). If the allurer fails a saving throw, it can choose to succeed instead.