Cherished by a long line of barbarian chieftains before the tribe was extinguished, the mauling mimic's origins remain shrouded in myth. The tribe's tale states that their first chieftain pulled this weapon from the blood of a primordial demon they slew, yet, all the monstrosity's descendants are clearly specialized mimics. It doesn't really matter as the creatures are quite potent weapons in the right hands or lethal predators without. Either way, skulls are going to get crushed.

Mauling Mimic

Medium monstrosity (shapechanger), neutral

Armor Class 12 (natural armor)

Hit Points

Speed 15 ft

Str 18 Dex 10 Con 16 Int 5 Wis 4 Cha 8

Saving Throws Str +6

Skills Stealth +4

Damage Resistances bludgeoning

Damage Immunities acid

Condition Immunities charmed, prone

Sensesdarkvision 60 ft, passive Perception 12

Languages Common, Elvish, Sylvan

Challenge 3 (700 XP)

Shapechanger.

The mimic can use its action to polymorph into a magical maul +1 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.

Crack Down.

If the mimic does more bludgeoning damage to a creature in a single round than its Hit Dice, the creature is knocked prone. If a creature is knocked prone in this way, the mimic may a melee attack against it as a reaction. This ability confers to a creature that has attuned to the mimic in its object form.

False Appearance (Object Form Only)

While the mimic remains motionless, it is indistinguishable from an ordinary pond basin

Grappler.

While the mimic remains motionless, it is indistinguishable from an ordinary, magical maul +1.

Magic Weapons.

The mimic's weapon attacks are magical.

Actions

Pseudopod.

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 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: 8 (1d8 + 4) piercing damage plus 4 (1d8) acid damage.

Hammer Home (Recharge 6).

The mimic explodes in a flurry of pseudopods 20ft long and 5ft wide before reforming either in its original position or at the end of the line. All creatures in the area of effect must succeed on a DC 14 Dexterity save or take 10 (3d6) bludgeoning damage. The mimic loses its Adhesive ability during this action. A creature attuned to the mimic in its object form may use Hammer Home 1/short rest independently of the mimic's Recharge. The creature may choose to move to the end of the line immediately after the action without provoking opportunity attacks.