Apparition

Ephemeral. The apparition can't wear or carry anything.

Familiar. The apparition can serve another creature as a familiar, forming a telepathic bond with its willing master, provided that the master is at least a 3rd-level spellcaster. While the two are bonded, the master can sense what the apparition senses as long as they are within 1 mile of each other. If its master causes it physical harm, the apparition will end its service as a familiar, breaking the telepathic bond.

Incorporeal Movement. The apparition can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Unusual Nature. The apparition doesn’t require air, food, drink, or sleep.

Life Drain. Melee Spell Attack: +3 to hit, reach 5 ft., one creature. Hit: 7 (3d4) necrotic damage. The target must succeed on a DC 10 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the creature finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.

Invisibility. The apparition magically turns invisible until it attacks or uses Scare, or until its concentration ends (as if concentrating on a spell).

Scare (1/Day). One creature of the apparition's choice within 20 feet of it must succeed on a DC 11 Wisdom saving throw or be frightened for 1 minute. The target can repeat the saving throw at the end of each of its turns, with disadvantage if the apparition is within line of sight, ending the effect on itself on a success.