(Book of Vile Darkness)

Enchantment [Evil]
Level: Sorcerer 2, Wizard 2, Assassin 3, Blackguard 3, Cleric 3, Pain 2,
Components: V, S, M,
Casting Time: 1 action
Range: Personal
Target: Caster
Duration: 1 round/level

For every 10 points of damage the caster deals in a given round while under the effect of this spell, she gains a +1 luck bonus on attack rolls, saving throws, and skill checks in the next round.
The more damage the caster deals, the greater the luck bonus.
It's possible to get a luck bonus for multiple rounds if she deals damage in more than one round during the spell's duration.
Material Component: A leather strap that has been soaked in human blood.