Up on the housetop, adventures pause

Suddenly caught by its jaws

Down through the chimney with lots of noise

All down the gullet, acid destroys

Oh, who wouldn't go? (Oh-oh-oh)

Who wouldn't go?

Up on the housetop, click, click, click

Down through the gullet with blood so slick

A bane of urban sprawl, the chimney mimic scurries from rooftop to rooftop, burrowing part of its body into the shingles. More akin to a spider in many respects, it can produce a flurry of many tentacles at once to tenderize its meals. Likewise, it can produce its own smoke to complete the illusion of being a chimney and blind its foes.

Chimney Mimic

Large Monstrosity (shapechanger), neutral

Armor Class 16 (natural armor)

Hit Points 67 (9d10 + 18)

Speed 15 ft

Climb 10 ft

Str 16 Dex 16 Con 15 Int 6 Wis 16 Cha 11

Skills Acrobatics +5, Stealth +7

Damage Immunities acid, fire

Condition Immunities prone, poisoned

Sensesdarkvision 60 ft, passive Perception 13

Languages -

Challenge 4 (1,100 XP)

Shapechanger.

The mimic can use its action to polymorph into a chimney 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. The mimic can activate and deactivate this ability as a bonus action.

False Appearance (Object Form Only)

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

Grappler.

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

Spider Climb.

The mimic can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Actions

Pseuedpod.

Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 8 (1d10 + 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: 8 (1d10 + 3) piercing damage plus 4 (1d8) fire damage.

Sweep (Recharge 5-6).

The mimic lashes out in a flurry of pseudopods in a 15ft cone. All creatures within the area of effect must succeed on a DC 13 Dexterity save or take 9(2d8) bludgeoning damage and be knocked prone. This action does not activate the mimic's adhesive trait.

Smoke Stack.

The mimic expels a puff of smoke and cinder in a 10ft cloud. The cloud spreads around corners, and its area is heavily obscured. It lasts for the next minute or until a wind of moderate or greater speed (at least 10 miles per hour) disperses it.