Crabwalk

(Spell Compendium, page 53, DnD 3.5)

Transmutation

Level: ; Bard 1; Druid 1; Ranger 1
Components: V, S, M
Casting Time: 1 standard action
Range: Touch
Target: Creature touched
Duration: 1 minute/level
Saving Throw: None
Spell Resistance: None

_The creature you touch now moves much faster, scuttling about with disconcerting ease.

When the subject of this spell charges, it gains a +4 bonus on its attack roll and takes no penalty to Armor Class. This benefit replaces the normal +2 bonus on attack rolls and -2 penalty to AC that a charge attack normally confers. If the creature is capable of multiple attacks after a charge, such as a lion with the pounce ability, the bonus applies only to the first attack.

Material Component: A crab's leg.