Beast Mimic

Adhesive (Amorphous Form Only). The mimic adheres to anything that touches it. A Huge or smaller creature adhered to the mimic is also grappled by it (escape DC 13). Ability checks made to escape this grapple have disadvantage.

Animal Forms. The mimic can use its action to polymorph into a CR 2 or lower Medium sized or smaller beast it has seen or back into its true, amorphous form. Its game statistics are replaced by the statistics of the beast, but it retains its hit points, alignment, personality, and its Intelligence, Wisdom, and Charisma scores. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies. 

False Appearance (Beast Form Only). While the mimic is in beast form, it is indistinguishable from an ordinary beast.

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

Multiattack. The mimic makes a Pseudopod attack and a Bite attack in its amorphous form. While in beast form, the number of attacks depends on the form chosen.

Pseudopod (Amorphous Form Only). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) bludgeoning damage. If the mimic is in object form, the target is subjected to its Adhesive trait.

Mimic Bite (Amorphous Form Only). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) piercing damage plus 4 (1d8) acid damage.