From Elemental Lords of Porphyra

Conch of Lies
Aura moderate transmutation; CL 5th; Weight 4 lbs.
Slot none; Price 12,800 gp
This large seashell is engraved with dire runes, and has a blowhole worked with a brass mouthpiece in one end. The first blast per day lowers the Will saving throw bonus of all who hear it within 60 ft. by 1. The second blast invokes the spell enthrall. Any subsequent blasts invoke the spell command, but any blast past the third incurs a 10% cumulative chance of shattering the conch of lies irrevocably. All blasts require a standard action, and all spells are cast at CL 5th.
Requirements Craft Wondrous Item, command, enthrall; Cost 6,400 gp