Most adventurers have either encountered or heard a story of an encounter with a mimic disguised as a chest. This is so common that everyone assumes a chest might just be a mimic. Hopefully, they never run across this monstrosity. Bred and trained by The Moneylender to protect his ill-gotten fortune, these mimics take the form of high-quality chests and possess greedy souls. They horde treasure and protect it fiercely. The more booty the mimic holds, the tougher it becomes - even more so when it robs the dead. If they get too aggressive, the Moneylender sells them off to other villains to populate their castles and dungeons.

Coffer Mimic

Medium monstrosity (shapechanger), neutral

Armor Class 12(natural armor)

Hit Points 52 (7d8 + 21)

Speed 15 ft

Str 17 Dex 12 Con 16 Int 5 Wis 11 Cha 14

Skills Deception +4, Stealth +5

Damage Resistances poison

Damage Immunities acid

Condition Immunities prone

Sensesdarkvision 60 ft, passive Perception 11

Languages -

Challenge 3 (700 XP)

Shapechanger.

The mimic can use its action to polymorph into a treaure-stuffed chest 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 13). 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 treasure-stuffed chest.

Grappler.

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

Lockbox (object form only).

All items within the mimic are subject to the Nondetection Spell.

Net Worth (Object Form Only).

The coffer mimic gains +1 Natural Armor for each 100 GP worth of coins and items within it.

Actions

Pseudopod.

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.

Bite.

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

Make it Rain (Recharge 4-6).

The mimic spews out coins, gems, and trinkets with explosive force in a 20ft radius around it. All targets in the area of effect must succeed on a DC 13 Dexterity save or take 13 (3d8) bludgeoning damage. The mimic's natural armor value falls by 1 to a minimum of +1

Reactions

Death and Taxes.

If the mimic reduces a creature to 0 hit points, it mystically absorbs all coins that creature is carrying. It regains 9 (2d8) hit points.