Melfs Unicorn Arrow

Conjuration
Level: Sorcerer/wizard 3
Components: V, S, F
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Target or Targets: One creature or up to five creatures, no two of which are more than 15 ft. apart
Duration: Instantaneous
Saving Throw: None
Spell Resistance: No
Focus: An ivory replica of a unicorn (25 gp)
Source: Player's Handbook II

The shimmering, transparent form of a unicorn flies forward, its corporeal horn lowered in a charge at its enemy.

A translucent unicorn shape appears in midair and speeds toward the target of this spell. If you succeed on a ranged touch attack, the horn slams into the target and deals 1d8+8 points of damage.
In addition, the target is subject to a bull rush, and must make a Strength check (with appropriate modifiers for a bull rush) against a DC of 21. If the check is failed, the subject is pushed back 5 feet, plus 5 feet for every 5 points by which it failed the check.
You can conjure an additional unicorn arrow for every three caster levels beyond 5th, up to five at 17th level. You can have them strike a single creature or several creatures, but each horn can strike only one creature. You must designate targets before you make your attack rolls. A creature struck by more than one horn is only required to make one Strength check to avoid the bull rush, but the DC of the check increases by 2 for each horn beyond the first that strikes it.