This cursed musical instrument radiates magic if detect magic is used. It appears as a normal horn, or possibly any of the magical ones. It will sound a note and call forth a mass of bubbles that completely surround and blind the individual who blew the horn for 2d10 rounds, but these bubbles appear only in the presence of a creature actively seeking to slay the character who played the horn, so their appearance might be delayed for a time.
Bards are actually able to use this cursed magical item to their advantage (once they determine what the horn is). When properly blown by a bard, the horn emits a cone of bubbles 30 feet long with a 30-foot diameter end. Anyone caught in the bubbles is effectively blinded for 2d10 rounds unless he rolls a successful saving throw vs. breath weapon. However, there is a 5% chance that the horn backfires and sucks the bard through it, emitting the hapless minstrel as a mass of bubbles. Once all of the bubbles pop (taking 2d10 rounds), the bard is irrevocably dead. Jesters (a bard kit) have only a 1% chance of being turned to bubbles.