Homunculus

A homunculus is a wizard's personal assistant, not a pet, not a familiar in the usual sense, and not a combatant. It is a Tiny construct with 4 HP and AC 13 that flies at 40 ft. and shares a Telepathic Bond with its master across any distance on the same plane. The whole point of the creature is that the master can route their senses, their voice, and one weird poison bite through a body that is not their own.

In play, the homunculus is a logistics tool. Send it through the keyhole to look at the cult meeting, then telepathically narrate what it sees back to the wizard. Use it to deliver written notes between PCs split across an estate. Park it in the rafters of a noble's hall and listen. With Darkvision 60 ft., a fly speed, and immunity to Poison and the Charmed condition, it goes places no PC can. It cannot speak, but it understands Common plus one other language, so any retort is the wizard relaying it through the bond.

When combat happens, the homunculus is a single-bite finisher, not a participant. The Bite hits at +4 for 1 piercing, but the rider is the real threat: DC 12 Con save, fail by 5 or more and the target is Unconscious for up to a minute (until they take damage). One unconscious mage during a duel is the entire encounter swung. The catch is that the homunculus dies to almost any single hit, so it must Bite from above, from behind, or from a position where the target does not get an opportunity attack. After the Bite, fly straight up 40 feet and land on a beam.

Treat the death of a homunculus as a real loss. By the rules its master can build another, but in fiction it took weeks of work and a piece of the master's body. The party should feel it when one falls.

A trick worth using: have the wizard PC describe a scene from the homunculus's perspective in second person. The narrative shift makes the bond feel like more than a stat block.

A hostile homunculus is almost always evidence of a hostile master. The party found a workshop, a noble's tower, a mage's tomb, and the little construct is the first thing to come buzzing out of the dark. It is not the encounter. It is the witness, the alarm, and the venom-tipped delivery system the wizard uses while their golem closes the distance.

Run the homunculus as a hit-and-run nuisance. With 40 ft. fly, AC 13, and 4 HP, it has one job: get within 5 feet of the squishiest target, Bite, and immediately fly back out of reach. The Bite at +4 only does 1 damage, but a failed DC 12 Con save by 5 or more drops the target Unconscious for the rest of the fight unless someone wakes them with damage. Spending an action to wake the wizard is a tempo cost the rest of the party pays.

The homunculus is also the master's eyes. Telepathic Bond means whatever it sees, the master sees, so killing it removes a scout but does not surprise the larger encounter. If the players smash it in round one, fine, but the real fight already knows where they are. Resolve that explicitly so the party feels the cost of having let it live for two rounds.

Have the homunculus mimic its master's posture and tics. The thing nodding at the doorway has the wizard's exact little headtilt. The party should feel watched.