Shapechanger. The mimic can use its action to polymorph into an animal skin or paper parchment 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 Medium or smaller creature adhered to the mimic is also grappled by it (escape DC 11). 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 parchment.

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

Innate Spellcasting. The mimic's innate spellcasting ability is Intelligence (spell save DC 10). The mimic can innately cast the following spells, requiring no material components:

At will: commune with nature

Skin Graph. The mimic can manipulate the pigmentation of its skin to form words.  The mimic is unable to speak, but can communicate by using an action to generate up to 25 words or a detailed image on its surface.  The mimic can erase anything written on its surface at will.

Spell Scroll. When first encountered, the mimic contains 1 random spell.  The mimic can only hold one spell, but the spell can be of any level.  The mimic can use an action to cast a spell it is holding, as though casting it from a spell scroll.  The mimic's spell casting ability is Intelligence, and spells of 1st-level or higher are considered of a higher level than it can normally cast.  When the mimic casts its held spell, the spell is no longer stored in it.

While the mimic isn't storing a spell, a non-hostile creature can cast a spell of 1st-level or higher into the mimic by touching the mimic as the spell is cast, or by copying a spell from a spellbook or spell scroll onto the mimic's surface.  If a creature stores a spell by casting it into the mimic, the spell has no effect, other than to be stored by the mimic.  While the mimic is holding a spell, it can be copied into a spellbook as though the mimic were a normal spell scroll.

Pseudopod. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) bludgeoning damage. If the mimic is in object form, the target is subjected to its Adhesive trait.

Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) piercing damage plus 2 (1d4) acid damage.