Your backpack suddenly developing teeth and tentacles was surprising to say the very least. You've been using it for months and the idea of it being a mimc is just unfathomable. But, now it's time to fight for your life. The same for the barbarian whose trusty ax has bent back to try and gnash him to pieces. The paladin's gear seems unaffected and now he's bellowing for a fiend to show itself. Is that chandelier dripping down to form something horned and a bit too spongy? Oh, this is going to be rough. Roll for initiative.

A strange creature spat from the bowels of Hell, the mimic mimic doesn't have a properly demonic name. Hell, it doesn't even have a sense of identity beyond finding itself onto the mortal play to make malicious mischief. Essentially a demon-shaped puddle. It can assume the form of any object and shares many traits a mimic does. It can also share the ability to become a mimic with a nearby object for a short time. Perhaps it was formed by mortals' sense of nameless dread, or because they cursed inanimate objects too much whenever they didn't work right or were in the way. Nevertheless, the mimic mimic is here now, and it's going to get messy.

Mimic Mimic

Large fiend (shapechanger), chaotic evil

Armor Class 12 (natural armor)

136 (16d10 + 48)

Speed 30 ft

Climb 30 ft

Str 19 Dex 12 Con 17 Int 12 Wis 14 Cha 16

Saving Throws Str +7, Con +6

SkillsDeception +6, Stealth +7

Damage Resistances fire

Damage Immunities acid, poison

Condition Immunities poisoned, prone

Sensesdarkvision 60 ft, passive Perception 12

Languages Abyssal, Common

Challenge 7 (2,900 XP)

Shapechanger.

The fiend can use its action to polymorph into an object or back into its true, spongy demonic 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 mimic adheres to anything that touches it. A Huge or smaller creature adhered to the mimic is also grappled by it (escape DC 15). Ability checks made to escape this grapple have disadvantage.

False Appearance (Object Form Only).

While the mimic mimic remains motionless, it is indistinguishable from an ordinary object.

Grappler.

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

Toxic Skin.

If a creature begins its turn grappled by the fiend, it takes 10 (3d6) acid damage.

Actions

Multiattack.

The mimic makes a bite and a pseudopod attacks.

Pseudopod.

MMelee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage. If the mimic is in object form, the target is subjected to its Adhesive trait.

Bite.

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 9 (1d10 + 4) piercing damage plus 9 (4d8) acid damage.

Corrupt Object.

The fiend chooses a Medium or smaller non-magical object it can see within 60ft. That creature becomes a mimic for the next minute under the fiend's control. The object returns to its original shape and nature after 1 minute, if Dispel Magic or a similar effect is used on it, or the mimic is reduced to 0 hit points. If the object is carried by a creature, the creature makes a DC 15 Charisma save with the object remaining unchanged on effect. If the mimic mimic uses this ability while in object form, it does not negate its False Appearance. The mimic mimic can only have 3 active mimics created this way at one time.

Reactions

Focus Death.

If the mimic reduces a creature to 0 hit points it may use its Corrupt Object on an object within 5ft of that creature.