There once was a mimic that came across a troll downed by an adventuring party, but not finished off. At first, it found the feast delightful and filling, then it found it bloating and painful until its acidic bites finally finished the giant off. As the mimic explored the troll's guts, it found that some of the creature’s regenerative ability transferred over to it. This came at the expense that it could only turn into a long, spindly form. However, it also noticed that dungeoneers always carried rope, and often needed more than it packed in. So, the mimic formed its chosen disguise and its descendants inhabit many a dungeon today. Sometimes they even pretend to be a magical rope that regrows when cut, until the prey is dangling over an abyss and deliciously easy to devour.

Gut Mimic

Medium monstrosity (shapechanger), neutral

Armor Class 14 (natural armor)

Hit Points 65 (10d8 + 20)

Speed 15ft

Climb 15ft

Str 18 Dex 16 Con 14 Int 5 Wis 13 Cha 8

Skills Stealth +7

Damage Immunities acid

Condition Immunities prone

Senses darkvision 60 ft., passive Perception 11

Languages -

Challenge 4 (1,100 XP)

Shapechanger.

The gut mimic can use its action to polymorph into up to 50ft of rope 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.

False Appearance.

While the gut mimic remains motionless, it is indistinguishable from an ordinary length of rope.

Grappler.

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

Regeneration. The gut mimic regains 10 hit points at the start of its turn. If the gut mimic takes fire damage, this trait doesn't function at the start of the gut mimic's next turn. The gut mimic dies only if it starts its turn with 0 hit points and doesn't regenerate.

Actions

Multiattack.

The gut mimic makes two pseudopod attacks.

Pseudopod.

Melee Weapon Attack: +6 to hit, reach 25 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 9 (2d8) acid damage.

Strangle (Recharge 6).

The gut mimic curls around a creature it has grappled and squeezes the air out of it. The creature takes 9 (2d8) acid damage and must succeed on a DC 14 Constitution save or lost consciousness and become Incapacitated until the end of its next turn. If the creature fails this save by 5 or more, it is reduced to 0 hit points instead and begins dying.