Cassisian

Transfer Protection. A non-evil creature can wear a willing cassisian as a helmet as a bonus action. While it does, the cassisian can take no actions, but the cassisian extends a +1 bonus to AC and saving throws against evil creatures to its wearer. At any time, the cassisian can detach itself from its wearer as an action.

Change Shape. The cassisian magically polymorphs into a humanoid or beast that has a challenge rating no higher than its own, or back into its true form. It reverts to its true form if it dies. Any equipment it is wearing or carrying is absorbed or borne by the new form (the cassisian's choice). In a new form, the cassisian retains its alignment, hit points, Hit Dice, ability to speak, proficiencies, and Intelligence, Wisdom, and Charisma scores, as well as this action. Its statistics and capabilities are otherwise replaced by those of the new form, except any class features or legendary actions of that form.

Eye Beams (Recharge 5-6). The cassisian releases beams of heat or cold from its eyes in a 15-foot line. Each creature in that line must make a DC 13 Dexterity saving throw, taking 2d6 cold or fire damage (cassisian's choice) on a failed save, or half as much on a successful one.

Headbutt. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d6) bludgeoning damage plus  2 (1d4) radiant damage.

Spellcasting. The cassisian casts one of the following spells, using Charisma as its spellcasting ability (spell attack modifier +2, spell save DC 10):

At Will: Light.

1/day each: Healing Word