This species of mimic observed the best way to lure prey in was to make sure that the meals had to come to it. While other monstrosities were chests, barrels, and the like, their prey had to be motivated to peek. Everyone needs to take the stairs to get from one level to another. The first breeds tested out various formats of said stairs, and some of those still exist by they rarely evolve past the run-of-the-mill mimic. This particular variation settled on spiral stairs. It found prey moved slowly on the stairs and could be easily disoriented with a quick spin. Also, each step made a perfect place for manifesting a multitude of tiny mouths to tenderize multiple foes. If worse comes to worst, it curls around a single meal and pulls it up to the next floor like a retracting tongue. Needless to say, these can be a bit of a hassle for many an adventurer and have been the end of many a common folk.

Spiral Mimic

Large monstrosity (shapechanger), neutral

Armor Class 15 (natural armor)

Hit Points 110 (13d10 + 39)

Speed 15 ft

Str 18 Dex 14 Con 16 Int 5 Wis 15 Cha 8

Skills Stealth +8

Damage Immunities acid

Condition Immunities prone

Sensesdarkvision 60 ft, passive Perception 12

Languages -

Challenge 5 (1,800 XP)

Shapechanger.

The mimic can use its action to polymorph into a spiral staircase 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 15). 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 spiral staircase.

Grappler.

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

Actions

Multiattack.

The mimic makes three pseudopod attacks.

Pseudopod.

Melee Weapon Attack: +7 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: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) piercing damage plus 4 (1d8) acid damage.

Nibble (Object Form Only) (Recharge 6).

The mimic manifests tiny mouths on each of its steps. Each creature currently using the stairs must succeed on a DC 14 Dexterity save or take 4(1d8) acid damage.

Spin (Recharge 5-6).

The mimic rapidly rotates around its axis, disorienting all the creatures that are adhered to it. All creatures that the mimic is grappling must succeed on a DC 14 Constitution save or be Incapacitated until the end of their next turn. If they fail this save by 5 or more, they are Stunned until the end of their next turn instead.