Ironthunder Horn

Transmutation [Sonic]
Level: Bard 1, sorcerer/wizard 2
Components: V, S
Casting Time: 1 standard action
Range: 30 ft.
Area: Cone-shaped burst
Duration: Instantaneous
Saving Throw: Reflex negates
Spell Resistance: Yes
The last words of your spell boom out with a thundering roar, knocking the foes in your path off their feet.
You create a deep resonant vibration that can shake creatures off their feet.
Creatures in the area must succeed on a Reflex saving throw or fall prone.