Shapechanger. The mimic can use its action to polymorph into a tower or turret, or back into its true, amorphous form. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Adhesive (Object Form Only). The mimic adheres to anything that touches it. A creature adhered to the mimic is also grappled by it (escape DC 18). Ability checks made to escape this grapple have disadvantage.

False Appearance (Object Form Only). While the mimic remains motionless, it is indistinguishable from an ordinary object.

Feculent Foundations. The ground in a 10-foot radius around the mimic is doughlike difficult terrain. Each creature that starts its turn in that area must succeed on a DC 18 Strength saving throw or be subjected to the mimic's Adhesive trait.

Grappler. The mimic has advantage on attack rolls against any creature grappled by it.

Innate Spellcasting. The mimic's innate spellcasting ability is Constitution (+9 to hit with spell attacks). The mimic can innately cast the following spells, requiring no material components:

At will: acid arrow

Towering Terror. Any enemy outside the mimic that starts its turn within 60 feet of it must succeed on a DC 18 Wisdom saving throw or be frightened until the start of the enemy’s next turn. If the enemy’s saving throw is successful, it is immune to this mimic's Towering Terror for the next 24 hours.

Multiattack. The mimic makes three pseudopod attacks, each of which it can replace with one use of Drop.

Pseudopod. Melee Weapon Attack: +10 to hit, reach 30ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage. If the mimic is in object form, the target is subjected to its Adhesive trait.

Bite. Melee Weapon Attack: +10 to hit, reach 5ft., one target. Hit: 19 (3d8 + 6) piercing damage plus 13 (3d8) acid damage. If the target is a Large or smaller creature, it must succeed on a DC 18 Strength or Dexterity saving throw (target's choice) or be swallowed by the mimic. A swallowed creature is blinded and restrained, has total cover against attacks and other effects outside the mimic, and takes 21 (6d6) acid damage at the start of each of the mimic's turns.

If the mimic takes 30 damage or more on a single turn from a creature inside it, the mimic must succeed on a DC 21 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the mimic. If the mimic dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 20 feet of movement, exiting prone.

Drop. One Large or smaller object held or creature grappled by the mimic is lifted up to 60 feet into the air and dropped into an unoccupied space within 5 feet of the mimic. At the end of a fall, the target takes 3 (1d6) bludgeoning damage for every 10 feet it fell. The creature lands prone, unless it avoids taking damage from the fall, and is subjected to the mimic's Feculent Foundations trait, unless it can avoid landing in an affected space.  If the target falls atop another creature, that creature must succeed on a DC 18 Dexterity saving throw or take the same damage and be knocked prone.

Tower Defense (Recharge 5–6). The mimic uses one of the following tower defense options.

Barrage. The mimic fires a barrage arrow-like quills in a 60-foot cone.  Each creature in that area must make a DC 17 Dexterity saving throw, taking 13 (3d8) piercing damage on a failed save, or half as much damage on a successful one.

Volley. The mimic fires a volley of arrow-like quills at nearby targets.  Each creature within 20 feet of the mimic must make a DC 17 Dexterity saving throw, taking 36 (8d8) piercing damage on a failed save, or half as much damage on a successful one.