Arcane Sight. The phaerimm discerns the location of all magical auras within sight and knows which creatures within 60 feet are spellcasters.

Extended Concentration. The phaerimm can concentrate on two different spells at the same time. If concentration is broken, then both spells fade immediately.

Immutable Form. The phaerimm is immune to any spell or effect that would alter its form.

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

Spellcasting. The phaerimm casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 19):

At will: mage hand, minor illusion, telekinesis

1/day each: chain lightning, confusion, dominate monster, greater invisibility, hold monster, mass suggestion, prismatic spray, reverse gravity

2/day each: crown of madness, detect thoughts, dominate person, fear, fireball, phantasmal force, magic missile, shield

Multiattack. The phaerimm makes four Claw attacks and then makes a Bite or Stinger attack. Alternatively, it uses Spellcasting and then makes two Claw attacks.

Bite. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit:18 (2d12 + 5) piercing damage.

Claw. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit:12 (2d6 + 5) slashing damage.

Stinger. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit:12 (2d6 + 5) piercing damage. If the target fails a DC 18 Constitution saving throw, they have the paralyzed condition for 1 minute. The phaerimm's poison forces the paralyzed target to float 5 feet above the ground. The target may repeat the saving throw at the end of each of it's turns.

Implant. The phaerimm makes a Stinger attack against a paralyzed target. If the stinger hits, an egg is implanted in the target. This egg can only be removed by spells that cure disease, such as lesser restoration. If the egg is not removed within 90 days, the larva emerges, and the host is killed. A phaerimm has a single egg so may only use this ability once.