Silence

Innate Spellcasting. The silence's innate spellcasting ability is Intelligence (spell save DC 15, +7 to hit with spell attacks). The silence can innately cast the following spells, requiring only verbal components:

At will: chill touch, lightning lure

Sneak Attack (1/Turn). The silence deals an extra 7 (2d6) damage when it hits a target and has advantage on the attack roll, or when the target is within 5 feet of an ally of the silence that isn't incapacitated and the silence doesn't have disadvantage on the attack roll.

Forgettable. Whenever a creature is no longer able to see a silence the target makes a mark on their arm, signifying that they have seen the silence. The target then forgets ever seeing the silence and must make a DC 15 Constitution saving throw. On a fail save, the target takes 2 (1d4) psychic damage and staggers back 5 feet. On a successful save, the target takes half as much damage and does not stagger.

Multiattack. The silence makes two attacks with its claws. Alternatively, it makes one attack with its claws and casts a spell.

Claws. Melee Weapon Attack: +3 to hit, reach 5 ft., one creature. Hit: 8 (2d6 + 1) piercing damage, plus 7 (2d4) necrotic damage. The target must succeed on a DC 15 Constitution saving throw or look away from the silence (causing the Forgettable feature to trigger).