Belief

Angelic Weapons. The belief's weapon attacks are magical. When the belief hits with any weapon, the weapon deals an extra 4d8 radiant damage (included in the attack).
Innate Spellcasting. The belief's spellcasting ability is Charisma (spell save DC 15). The belief can innately cast the following spells, requiring no material components:
At will: detect evil and good
1/day each: commune
Life Sap. When the belief succeeds in grappling a creature, the target creature takes 3d6 necrotic damage, and the belief regains hit points equal to half the amount of necrotic damage dealt. Until the grapple ends, the grappled creature takes this necrotic damage again at the start of each of the belief's turns.
Magic Resistance. The belief has advantage on saving throws against spells and other magical effects.

Multiattack. The belief makes one stomp attack and one tentacle attack.
Tentacle. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage plus 18 (4d8) radiant damage, and the target is grappled.
Stomp. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 22 (3d10 + 6) bludgeoning damage, and the target is knocked prone.
Immobilizing Gel (Recharge 5-6). The belief spits a globule of sticky green tar at a point on the ground of its choice within 30 feet. This tar acts as difficult terrain.
Each creature that starts its turn in the tar must make a DC 17 Dexterity saving throw. On a failed save, the creature is restrained as long as it remains in the tar or until it breaks free.
A creature restrained by the tar can use its action to make a DC 15 Strength check. if it succeeds, it is no longer restrained.