Testing the item for magical properties will reveal Superb summoning and charm magic at work. A Great test of divination magic will reveal the powers of the device. The Horn can be sounded five times per day. One of six notes can be played each time the instrument is used.
- Call of the Worm - This note summons forth a vast swarm of earthworms, which can be commanded by the Horn's user to burrow through the earth. The swarm of worms is capable of digging through a ten foot cubic area of soil per round. The swarm lasts for ten rounds.
- The Hornet's Buzz - This reverberant note summons forth a swarm of six to eight giant hornets, who can be commanded to attack any nearby target. Each hornet has Average toughness, Good flight ability, and Good bite and sting attacks. Stings inject Good paralytic poison. The hornets remain for up to ten rounds, vanishing when slain.
- Mosquito's Whine - This irritating, high-pitched note seems to hang in the air after it is played. It's lingering sound drives away all manner of insects, mundane or magical, keeping them one hundred feet away from the place the Horn was sounded.
- The Moth's Whisper - This note, so soft it can barely be heard, summons a large moth to the Horn's user. The summoner can whisper a brief message and a person's name to the moth, which will seek out the named individual and delivery the message. The moth has Great stealth ability and flies at Good speed. It can fly up to twenty miles before it expires.
- The Swarm's Call - A reverberant note that hangs in the air, summoning all manner of biting and stinging insects to the Horn's owner. These creatures form a 20 foot radius cloud around the summoner, inflicting Fair damage on anyone that enters the cloud other than their master. This swarm lasts ten rounds and can only be harmed by area of effect attacks.
- Locust Song - This high-pitched note summons forth a horde of locusts who form a mile wide swarm around the summoner. This swarm can be set in motion by the summoner and once moving, it will consume all plant life in its path. The swarm moves five miles per day and lasts seven days.