Actions

Multiattack.

The dream vestige uses its frightful presence. It then makes four tendril attacks.  

Tendril.

Melee Weapon Attack: +10 to hit, reach 15 ft., one creature. Hit: 15 (3d6 + 5) necrotic damage. The target's Intelligence score is reduced by 1d4 and the dream vestige gains 5 temporary hit points. If this reduces the target’s Intelligence to 0, it dies and its body is engulfed and destroyed by the vestige, leaving nothing behind. Otherwise, the reduction lasts for 1 hour.  

Frightful Presence.

Each creature of the dream vestige’s choice that is within 60 feet of the dream vestige must succeed on a DC 18 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the dream vestige’s Frightful Presence for the next 24 hours.  

Dream Travel.

The dream vestige plane shifts from the Material Plane to the Plane of Dreams, or from the Plane of Dreams to the Material Plane. For every minute the vestige moves though the Plane of Dreams, it travels the equivalent of 5 miles in the waking world. The dream vestige always knows where it will come out in the waking world before using this action.