Monster Manual, p. 256
Innate Spellcasting (Psionics). The quaggoth's innate spellcasting ability is Wisdom (spell save DC 11). The quaggoth can innately cast the following spells, requiring no components:
Wounded Fury. While it has 10 hit points or fewer, the quaggoth has advantage on attack rolls. In addition, it deals an extra 7 ( 2d6 ) damage to any target it hits with a melee attack.
Multiattack. The quaggoth makes two claw attacks. Claw. Melee Weapon Attack: +5 to hit, reach 1 sq., one target. Hit: 6 ( 1d6+3 ) slashing damage.
Underdark