Multiattack. The yagnoloth makes one massive arm attack and one electrified touch attack, or it makes one massive arm attack and teleports before or after the attack.

Electrified Touch. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 27 (6d8) lightning damage.

Massive Arm. Melee Weapon Attack: +8 to hit, reach 15 ft., one target. Hit: 23 (3d12 + 4) bludgeoning damage. If the target is a creature, it must succeed on a DC 16 Constitution saving throw or is stunned until the end of the yagnoloth's next turn.

Life Leech. The yagnoloth touches one incapacitated creature within 15 feet of it. The target takes 36 (7d8 + 4) necrotic damage, and the yagnoloth gains temporary hit points equal to half the damage dealt. The target must succeed on a DC 16 Constitution saving throw, or its hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest, and the target dies if its hit point maximum is reduced to 0.

Battlefield Cunning (Recharge 4–6). Up to two allied yugoloths within 60 feet of the yagnoloth that can hear it can use their reactions to make one melee attack each.

Teleport. The yagnoloth magically teleports, along with any equipment it is wearing or carrying, up to 60 feet to an unoccupied space it can see.