Not all mimics like their food raw with the hearth mimic being the prime example. Originally charmed by a archmage, the hearth mimic served as his cooking fire, garbage disposal, and guard dog for years. When heroes slew the magus and took the tower over, the mimic saw no reason to alter the arrangement. It wasn't long before its decedents made their way into other venues. Sometimes they are menaces lurking within abandoned houses, other times helpful servants as long as they are kept placated. Every single one is exceedingly hesitant to attack cats and dogs, having developed an affection for the critters most frequently curled before their flames.

Hearth Mimic

Large monstrosity (shapechanger), neutral

Armor Class 16 (natural armor)

Hit Points 71 (11d8 + 22)

Speed 15ft

Str 18 Dex 10 Con 16 Int 5 Wis 14 Cha 8

5 Skills Stealth +4

Damage Resistances bludgeoning, piercing, and slashing from nonmagical attacks that aren't adamantine

Damage Immunities acid, fire

Condition Immunities prone

Sensesdarkvision 60 ft., passive Perception 12

Languages -

Challenge 4 (1,100 XP)

Shapechanger.

The mimic can use its action to polymorph into a fireplace 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 Huge or smaller creature adhered to the mimic is also grappled by it (escape DC 14). Ability checks made to escape this grapple have disadvantage. The mimic can activate and deactivate this ability as a free action.

False Appearance (Object Form Only).

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

Grappler.

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

Oven Baked.

If the mimic starts its turn grappling a creature hit by its Bite attack, it may use its bonus action to deal 7 (2d6) fire damage.

Actions

Pseudopod.

Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 8 (1d8 + 4) bludgeoning damage. If the mimic is in object form, the target is subjected to its Adhesive trait.

Bite.

Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 8 (1d8+4) piercing damage and 4 (1d8) acid damage. If the mimic is in object form, the target is subjected to its Adhesive trait as long there is not a creature currently grappled by the Bite attack. The mimic cannot use its Bite attack if it currently has a creature grappled by the Bite attack.

Breathe Fire. (Recharge 6)

The mimic exhales fire in a 15-foot cone. Each creature in that area must make a DC 13 Dexterity saving throw, taking 24 (7d6) fire damage on a failed save, or half as much damage on a successful one.