Aberrant crowd

A group of happy, smiling commoners wades into the festival crowd and joins in the celebration. Once surrounded by other festival goers, the heads of the commoners split across the middle, opening to reveal toothy maws, and the people are suddenly one writhing mass, their bodies connected by tendrils. The creature begins to devour the real crowd around it.

An aberrant crowd is a single huge creature capable of appearing as a group of 20-30 humanoids, usually human commoners, but equally able to appear as elven aristocrats or dwarven laborers. Travelling the countryside disguised as a group of pilgrims or merchant caravan, the crowd looks for a large group of humanoids, such as at a festival, wedding, or religious service. It then works its way in before revealing its true form and eating as many creatures as it can, before disguising itself again and moving on.

Huge aberration, Chaotic Evil

Armor Class: 15 (natural armor)
Hit Points: 121 (18d8+40)
Speed: 30 ft.

STR: 16 (+3)
DEX: 10 (+0)
CON: 18 (+4)
INT: 12 (+1)
WIS: 12 (+1)
CHA: 13 (+1)

Saves: Constitution: +8, Wisdom +5
Skills: Perception: +5, Deception: +5
Damage Resistances: Poison, Psychic
Condition Immunities: Charmed, Frightened, Grappled, Poisoned, Prone, Restrained
Languages: Common, Deep Speech
Challenge: 9 (5,000 xp)

Magic Resistance: The aberrant crowd has advantage on saving throws against spells and other magical effects.

Illusory Crowd: As an action the aberrant crowd can magically make itself look like a group of 20-30 separate humanoids of its choosing, all standing in a group. The illusory creatures can move, manipulate objects, and speak independently, but never get more than 5ft. from each other. A DC 16 Investigation check, or physical interactions with the crowd, reveals the illusion.

ACTIONS:

Multi-attack: The crowd makes 5 attacks with its Bite, only two of which can be on the same target.

Bite: Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6+4) piercing damage.