Bites

Melee Weapon Attack: +5 to hit, reach 0 ft., one creature in the swarm's space. Hit: 14 (4d6) piercing damage, or 7 (2d6) piercing damage if the swarm has half of its hit points or fewer. The target must succeed on a DC 15 Dexterity saving throw or one randomly determined magic item in its possession is immediately affected by the Mana Erosion trait. A spellcaster hit by this attack must succeed on a DC 15 Charisma saving throw or one of its lowest-level, unused spell slots is expended.