Curse

Evasion. If the curse is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, the curse instead takes no damage if it succeeds on the save and only half damage if it fails. It can’t use this trait if it has the Incapacitated condition.

Magic Resistance. The curse has Advantage on saving throws against spells and other magical effects.

Pack Tactics. The curse has Advantage on an attack roll against a creature if at least one of the curse’s allies is within 5 feet of the creature and the ally doesn’t have the Incapacitated condition.

Multiattack. The curse makes three attacks, using Stinger or Light Crossbow in any combination.

Stinger. Melee Attack Roll: +7, reach 5 ft. Hit: 11 (2d4 + 6) Piercing damage plus 24 (7d6) Poison damage, and the target has the Poisoned condition until the start of the curse’s next turn.

Light Crossbow. Ranged Attack Roll: +7, range 80/320 ft. Hit: 13 (2d8 + 4) Piercing damage plus 24 (7d6) Poison damage.

Read Thoughts. The curse casts Detect Thoughts, requiring no spell components and using Intelligence as the spellcasting ability (spell save DC 14).

Invisibility. The imp casts Invisibility on itself, requiring no spell components and using Charisma as the spellcasting ability.

Unsettling Visage (Recharge 6). Wisdom Saving Throw: DC 14, each creature in a 15-foot Emanation originating from the curse that can see the doppelganger. Failure: The target has the Frightened condition and repeats the save at the end of each of its turns, ending the effect on itself on a success. After 1 minute, it succeeds automatically.

Cunning Action. The curse takes the Dash, Disengage, or Hide action.

Shape-Shift. The curse shape-shifts into a Large, Medium, or Small creature, or it returns to its true form. Its game statistics, other than its size, are the same in each form. Any equipment it is wearing or carrying isn’t transformed.

Silvery Barbs. The curse casts Silvery Barbs on itself, requiring no spell components and using Intellegents as the spellcasting ability.

Sentinel. When the curse hits a creature with an opportunity attack, the creature's speed becomes 0 for the rest of the turn. Creatures provoke opportunity attacks from the curse even if a creature takes the Disengage action before leaving their reach. Additionally, when a creature within 5 feet of the curse makes an attack against a target other than them (and that target doesn't have this sentinel feat), they can use their reaction to make a melee weapon attack against the attacking creature.