Carrion Swarm

You Shape-Shift into a swarm of blood sucking pests until the start of your next turn, along with everything you are wearing and carrying. The spell ends early if you drop to 0 Hit Points. While in this form, you gain the following benefits.

Flying Pest. You have a Fly Speed of 60 ft., and no other movement speeds.

Tiny Pest. You can enter and occupy the space of other creatures, and do not provoke Opportunity Attacks. You can also pass through narrow openings as though you were a Tiny creature, but you treat liquids as solid surfaces. If the spell ends while you are in a space smaller than what you can normally occupy, you are shunted to the nearest unoccupied space, and have the Prone condition.

Annoying Pest. You have Resistance to Bludgeoning, Piercing, and Slashing damage, and have Immunity to the Prone, Grappled, and Restrained conditions.

Resilient Pest. You have Advantage on Strength, Dexterity, and Constitution saving throws.

Silent Pest. You can't speak or manipulate objects, and any objects you were carrying or holding can't be dropped, used, or otherwise interacted with. You also can't cast spells or make attacks other than those granted by this spell.

Harmful Pest. When you cast this spell, you can make up to three Melee Spell Attacks. You can make each attack at any point during your turn against a creature whose space you occupy. On a hit, the target takes 5d4 Necrotic damage, and you regain Hit Points equal to half the Necrotic damage dealt.

Using a Higher-Level Spell Slot. The damage increases by 1d4 per level of spell slot above 5.