Shapechanger. The mimic can use its action to polymorph into a cauldron 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 Large or smaller creature adhered to the mimic is also grappled by it (escape DC 12). 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 cauldron.

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

Pseudopod. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) bludgeoning damage. If the mimic is in object form, the target is subjected to its Adhesive trait.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) piercing damage plus 3 (1d6) acid or poison damage (mimic's choice).

Spew Brew.  A random alchemical concoction spews from the mimic's mouth in a 15 foot cone.  Roll a d12 to determine what concoction the mimic spews.  Each creature in the area must succeed on a DC 12 Dexterity saving throw or be is subjected to the concoction as though by normal means; a creature can choose to fail this saving throw if it wishes.