Traits

Gemstone Lure. The gem on the Carbuncle's forehead glows. A creature that can see it and is within 30 feet must make a DC 13 Wisdom save when it chooses to attack the Carbuncle. On a failure, it cannot target the Carbuncle that turn (it may choose another target or spend its turn on something else). A creature that succeeds on the save is immune to this feature for 24 hours.

Magic Resistance. The Carbuncle has Advantage on saving throws against spells and other magical effects.

False Friend. Information the Carbuncle conveys telepathically always sounds convincing. A Wisdom (Insight) check to realize the Carbuncle is deliberately lying has DC 15.

Actions

Bite. Melee Attack Roll: +5, reach 5 ft. Hit: 6 (1d4 + 3) Piercing damage.

Beguiling Whisper (Recharge 5–6). Wisdom Saving Throw: DC 13, one creature the Carbuncle can see within 60 feet. Failure: The target is Charmed by the Carbuncle for 1 minute. The Charmed target tends to follow reasonable suggestions the Carbuncle makes telepathically (except suggestions that would harm itself). The effect ends immediately if the target takes damage or the Carbuncle attacks it. The target can repeat the save at the end of each of its turns.

Reactions

Slip Away. When the Carbuncle is hit by an attack, it can spend half its movement to withdraw without provoking an Opportunity Attack.

How to Use

Carbuncle is a social trap, not a combat monster. If you use it in a fight, you waste its design.

Proper use: The party finds it in a cave/forest as a "wounded, cute, talking" creature. It asks for help telepathically. It joins the party. Then it:

• Misdirects them ("this path is safe" — it isn't)
• Steals a gem/treasure
• Flees at a critical moment or leaks information to the enemy

False Friend is critical: DC 15 Insight is, in a Lv2–4 party, beatable but not guaranteed. This makes the Carbuncle unpredictable.

Balance Note

There's a danger in Beguiling Whisper: the phrase "the Charmed target follows suggestions" can slide into the DM controlling the player's character. Boundary: the Charmed character makes their own decisions — they simply cannot act hostile toward the Carbuncle and find its words reasonable. Don't tell the player "you do this"; say "the Carbuncle tells you this and it sounds very sensible to you."