Mammonite

Mammonite uses a certain amount of Zeny to deal high damage to an opponent. The amount of zeny used can be reduced by 10% if the user has the quest skill Unfair Trick.

Trivia

 * The dictionary definition for mammonite is "avarice or greed; riches or wealth regarded as a source of evil and corruption," which is ironic considering this skill requires you to throw away money in order to cause damage.