There once was a blacksmith who got rich and famous, at least for his area, thanks to the help of some local fey. The wee folk were happy to help, in the beginning at least. At first, the blacksmith knew his place and gave them proper praise and gifts. But as his wealth grew, so did his ego. Once he'd crossed that line and hurt the fey's feelings, he had to be punished. This came in the form of a new 'enchanted' anvil gifted to him for being the best blacksmith ever. It ended up just being a mimic sculpted by fey magic. The blacksmith with a big head ended up having a very flat head, as did his family who came to investigate, his customers who came to pick up items, and then the local law who came to check out why folks weren't coming back from the shop. Since then these mimics have spread far and wide. Oh, they've eaten a few helpful fey too but the old adage about omelets and eggs applies just as well to anvils and heads... or... something like that.

Anvil Mimic

Medium Monstrosity (shapechanger), neutral

Armor Class 17 (natural armor)

Hit Points 75 (10d8 + 30)

Speed 15 ft

Str 18 Dex 12 Con 16 Int 5 Wis 13 Cha 8

SkillsStealth +5

Damage Resistances bludgeoning

Damage Immunities acid, fire

Condition Immunities prone

Sensesdarkvision 60 ft, passive Perception 11

Languages -

Challenge 4 (1,100 XP)

Shapechanger.

The mimic can use its action to polymorph into a anvil 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.

Brain (Object Form Only).

If the mimic moves at least 10ft. toward a target and then hits it with a slam attack on the same turn, the target takes an extra 9(2d8) bludgeoning damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be knocked prone. If the target is prone, the mimic can make a bite attack against it as a bonus action.

False Appearance (Object Form Only).

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

Grappler.

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

Out of Sight, Into Mind (Object Form Only).

As part of its movement, the mimic can instantly appear to any point it can see within 10ft using an equal amount of movement.

Strike While It's Hot.

The mimic has Advantage on attacks against creatures that have taken fire damage since the mimic's last turn.

Actions

Multiattack.

The mimic makes two Pseudopod attacks.

Pseudopod.

Melee Weapon Attack: +6 to hit, reach 5 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 plus 4 (1d8) acid damage.

Slam (Object Form Only).

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (1d10 + 4) bludgeoning damage.