Devil's Sight. Magical darkness doesn't impede the abyssal imp's darkvision.

Magic Resistance. The abyssal imp has advantage on saving throws against spells and other magical effects.

Sting. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) piercing damage, and the target must make a DC 11 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful one.

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

Annoying Mockery. The imp attempts to use Vicious Mockery, but for the life of it, it cannot seem to do more than annoy the enemy. Target that can be seen within earshot must make a DC 12 Wisdom saving throw. On a failed save, target's next attack throw is made on disadvantage, with no effect on a successful one.