Swarm of Shardlings (5e Creature)
From D&D Wiki
Swarm of Shardlings
Medium swarm of Tiny elementals (shardling), lawful good
Skills Arcana +7, History +7
Innate Spellcasting (Psionics). The swarm's innate spellcasting ability is Intelligence (spell save DC 13, +5 to spell attacks). The swarm can cast the following spells innately, requiring no material components:
At will: blur, light, mage hand (the hand is invisible), meld into stone, minor illusion, tongues
Immutable Form. The swarm is immune to any spell or effect that would alter its form.
Sense Thoughts. The swarm senses thoughts within 120 feet of it at will. This trait otherwise works like the detect thoughts spell but isn't itself magical.
Swarm. The swarm can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Tiny shardling. The swarm can't regain hit points or gain temporary hit points.
Slash. Melee Weapon Attack: +5 to hit, reach 0 ft., one target in the swarm's space. Hit: 10 (2d6 + 3) slashing damage, or 6 (1d6 + 3) slashing damage if the swarm has half its hit points or fewer.
Shardlings tend to gather in large groups because the psionic resonance between them makes their powers stronger, unlocking new abilities such as the power to calm the emotions of others and the power to avoid magical detection. The tiny green shards all moving in unison can be a wondrous sight to behold, and many artists have hunted for lifetimes just to glimpse the beauty and majesty of the flying crystals.
Elemental Nature. A swarm of shardlings doesn't require air, food, drink, or sleep.