Crystalline Mnemosynth

Amorphous Crystal. The Mnemosynth can move through a space as narrow as 1 inch wide without squeezing, its body refracting and reassembling through cracks in stone and crystal.

Psionic Crystal Body. Whenever the Mnemosynth takes lightning or thunder damage, it takes an additional 10 (3d6) psychic damage as resonance fractures ripple through its structure.

Memory Prism. The Mnemosynth stores fragments of memories stolen from creatures. While it has at least one stored memory, it has advantage on Deception checks and saving throws against being charmed or frightened. If reduced to 0 hit points, all stored memories are released in a psychic pulse; creatures within 30 feet must succeed on a DC 17 Wisdom saving throw or be stunned until the end of their next turn.

Refraction Simulacra. The Mnemosynth can create up to three Crystal Echoes at a time. Each echo appears as a translucent, faceted humanoid formed from refracted memory and crystal.

• Each echo has AC 13 and 30 hit points.
• An echo shares the Mnemosynth’s senses.
• Destroying an echo deals no damage to the Mnemosynth.

Multiattack. The Mnemosynth makes two Crystalline Pseudopod attacks.

Crystalline Pseudopod. Melee Weapon Attack: +7 to hit, reach 10 ft., one target.
Hit: 17 (3d8 + 4) psychic damage plus 9 (2d8) slashing damage as razor facets tear through mind and flesh.

Memory Fracture (Recharge 5–6). The Mnemosynth emits a focused psionic resonance at one creature it can see within 60 feet. The target must succeed on a DC 17 Intelligence saving throw or take 36 (8d8) psychic damage and be stunned until the end of its next turn. On a success, the target takes half damage and is not stunned. If the target fails the save by 5 or more, the Mnemosynth steals a fragment of the target’s memory (DM discretion: disadvantage on one ability check or saving throw of the Mnemosynth’s choice until the end of the target’s next long rest).

Create Crystal Echo (Recharge 6). The Mnemosynth extrudes a new Crystal Echo in an unoccupied space it can see within 30 feet.

Facet Shift. The Mnemosynth teleports up to 30 feet to an unoccupied space it can see that contains stone or crystal, leaving behind a brief afterimage of refracted light.

Psychic Refraction. When the Mnemosynth is targeted by a spell that requires an Intelligence, Wisdom, or Charisma saving throw, it gains advantage on the saving throw. On a success, the caster takes 10 (3d6) psychic damage.