Telepathic Bond. While the homunculus is on the same plane of existence as its master, it can magically convey what it senses to its master, and the two can communicate telepathically.
Actions
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 1 piercing damage, and the target must succeed on a DC 10 Constitution saving throw or be poisoned for 1 minute. If the saving throw fails by 5 or more, the target is instead poisoned for 5 (1d10) minutes and unconscious while poisoned in this way.
RollQuest summary Condition immunities: charmed, poisoned. Senses: darkvision 60 ft., passive Perception 10. Languages: understands the languages of its creator but can't speak. Speed: 20 ft., fly 40 ft.
RollQuest ships the D&D 2014 SRD as a content pack, on a 5e character sheet that does the maths - roll from the sheet and let the numbers work themselves out. Free to start.