Ancient Sepher

Shapechanger. The Sepher can use its action to polymorph into a beast form that resembles a frog (speed 20 ft., swim 40 ft.), an owl (20 ft., fly 60 ft.), bat (20ft., fly 40 ft.), or a spider (20 ft., climb 30 ft.), or back into its true form. Its statistics are the same in each form, except for the speed changes noted. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Blindsight. The Sepher can perceive it's surroundings through the flow of air and water.

Magic Resistance. The Sepher has advantage on saving throws against spells and other magical effects.

Unusual Nature. The Sepher doesn’t require food, drink, or sleep and it can squeeze through spaces as narrow as one inch. While motionless, Sephers are difficult to see while emerged in air or water, which allows it to hide in plain sight.

Sting (Bite in Beast Form). Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 5 (1d8 + 4) piercing damage, and the target must make a DC 14 Constitution saving throw, taking 15 (3d8) cold damage on a failed save, or half as much damage on a successful one.

Magical Gift (1/Day). The Sepher targets a creature it can see within 5 feet of it. The target gains a supernatural charm from the supernatural charms table or one time use of a spell of up to 5th level. The spell can be cast without spending a spell slot or providing any components.

Spellcasting. The Sepher casts one of the following spells, requiring no material or verbal components:

At will: druidcraft, guidance, pass without trace, resistance, wind walk

Natural Shelter. The Sepher magically takes shelter inside a rock, a living plant, or a natural source of fresh water in its space. The Sepher can’t be targeted by any attack, spell, or other effect while inside this shelter, and the shelter doesn’t impair the Sepher's blindsight. The Sepher can use its action to emerge from a shelter. If its shelter is destroyed, the Sepher is forced out and appears in the shelter’s space, but is otherwise unharmed.

Invisibility. The Sepher magically turns invisible until it attacks or until its concentration ends (as if concentrating on a spell). Any equipment the Sepher wears or carries is invisible with it.