The abandoned theater proved spooky enough, especially when hunting supposed ghosts haunting the building. But clearly, something of flesh and blood lived here, a hungry something by the chewed-on corpses left behind. A giant spider perhaps? Ghouls? You spotted the golden harp your party was hired to find. As it was rumored to be magical, you weren't all that surprised when it started talking. The instrument was happy that it'd finally be taken away from this place and also let you know about a bejeweled cup over there as an additional reward. Score! As you turned away, the harp's mouth filled with teeth, its strings tentacles. This might not even get to initiative.

The harp mimics can be traced back to a monstrosity adopted and raised by a bard, unsurprisingly. Said bard fed it a steady diet of rats and birds as they played the less-than-savory circuits. The mimic also took care of patrons that got a bit too handsy, of course. Over time, the bard even taught it to talk and educated it in a few classics. The mimic came to have a keen mind for its kind, and a quick wit. It also learned a few tricks to help the bard in their schemes and get them out of scrapes. After the bard passed, the mimic taught its spawn much the same and now they can be found on occasion across the region.

Harp Mimic

Medium Mimic (shapechanger), neutral

Armor Class 13 (natural armor)

75 (10d8 + 30)

Speed 15 ft

Str 16 Dex 12 Con 16 Int 12 Wis 11 Cha 14

Skills Deception +4, Persuasion +4, Stealth +5

Damage Resistances thunder

Damage Immunities acid

Condition Immunities prone

Sensesdarkvision 60 ft, passive Perception 10

Languages The native language of a creature touching it.

Challenge 4 (1,100 XP)

Shapechanger.

The mimic can use its action to polymorph into a magic harp 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.

Charming Harp (Object Form Only).

The mimic functions as a magical harp that allows a creature using it to access both its Fool's Gold Action and Inspire Bonus action. If the creature using the mimic is a bard, they gain advantage on Deception and Persuasion rolls against creatures with an intelligence of 10 or less.

False Appearance (Object Form Only).

While the mimic remains motionless, it is indistinguishable from an 'ordinary' magic harp.

Grappler.

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

Actions

Multiattack.

The mimic makes two attacks.

Pseudopod.

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 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: 7 (1d8 + 3) piercing damage plus 4 (1d8) acid damage.

Sonic Harpoon.

Ranged Weapon Attack: +4 to hit, range 15/30 ft., one target. Hit: 5 (1d6+2) piercing damage plus 4 (1d8) thunder damage. In addition, a creature must succeed on a DC 13 Constitution save or reduce it's speed by half and be Silenced until the end of its next turn.

Fool's Gold.

The mimic chooses a Medium or smaller object that it sees within 30ft and instills an illusion it is more valuable that it is for the next 24 hours, DC 12 to Detect. The mimic can use this ability without compromising false appearance and on other mimics in object form.

Bonus Actions

Inspire (2/long rest).

The mimic chooses a creature it can see within 30ft and gives it a d6 Bardic Inspiration die that functions exactly the same as Bardic Inspiration. If that creature is a monstrosity, it rolls 2d6 and chooses the highest when using this Bardic Inspiration die.