Innate Spellcasting.

The arcanaloth's innate spellcasting ability is Charisma (spell save DC 15). The arcanaloth can innately cast the following spells, requiring no material components:

At will: alter self, darkness, heat metal, invisibility (self only), magic missile

Magic Resistance.

The arcanaloth has advantage on saving throws against spells and other magical effects.

Magic Weapons.

The arcanaloth's weapon attacks are magical.

Spellcasting.

The arcanaloth is a 16th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 17, +9 to hit with spell attacks). The arcanaloth has the following wizard spells prepared:

Actions

Claws.

Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (2d4 + 3) slashing damage. The target must make a DC 14 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful one.

Teleport.

The arcanaloth magically teleports, along with any equipment it is wearing or carrying, up to 60 feet to an unoccupied space it can see.

Arcanaloth